That's a developer's preview, you must have read over that bit. Sources have been released now, but not complete. The release of Android L will be later this year, I don't see the point of porting that yet, since a lot of things are still going to change. I didn't flash the developer's preview on my Nexus 7 2013 even because it's not as functional as KitKat yet.
For those of us still using this phone, there's no harm in waiting on a ROM right. As long as it's healthy, just checking the thread every few days. I don't use my Skate anymore as my daily phone so there's no rush for me. I think you're exaggerating a bit, there's only one message a day in this thread, no-one is wasting their life here.
And I do think the ROM will be released some day, but as I said, there's no rush.
So does the N4 16GB cost €340 in your country? I'd say that's still a bargain, would be worth the €40 over budget for me.
If you're considering other brands, I can give you my 2 cents on Sony phones: the media features and apps are very good and when a new device gets released the features are often ported to older devices. But Sony isn't popular in the US, which means the amount of developers is limited and you need to be lucky. I think most devices have 1 or 2 good devs, but the lower end devices aren't supported for very long. There's FXP that's supposed to support all Xperia devices but in reality most of the work goes to the current flagship and when a new one arrives the old one gets dropped pretty quickly. A negative thing of Sony is that most of their LCD's aren't good at showing blackness.
Samsung devices get a lot more attention (and faster factory updates), but IMO the stock firmware is ugly and I'm not a fan of how they keep on sticking to the hardware menu key.
In comparison, the N4 has a great screen, great GPU, great software support... Only thing against it is storage on the device.
Doesn't Android scan /sdcard/media/audio/notifications (or ringtones) or /sdcard/Notifications for ringtones/alarm sounds? Facebook and Google Hangouts save their sounds there and Android picks that up without having to do anything.
Sony Xperia T costs €250 in Belgium at the moment (€100 cashback action), tilal has one ;-), so ROM support should be okay. Maybe there's a similar action in Portugal?
The Xiaomi Mi2 might be better, but you have to import it. There are some other pretty good Chinese phones you could import. Not ZTE or Huawei though, their latest phones are pretty underwhelming...
I wouldn't buy anything with a screen resolution of less than 720p anymore, that rules out the Acer. If you'd spend a little more and get your hands on a Nexus 4, that would also be a good solution I think.
I only looked at some screenies of MailDroid, you're right, it's ad-supported. Too bad. I was already wondering what the difference was with the paid (and hugely expensive) version. I use Gmail myself, so I don't know of any other mail apps aside from K9 mail (I installed that one on my girlfriend's phone), but that is one of the worst looking apps .. ever.
I recognize that perfectionism from my own work, I don't want others to see any of my development either unless it's 100% finished (Labview applications that is, nothing Android related). But that can be a very paralyzing attitude, you can never discover all bugs by beta testing on your own. I once lost weeks of work because of issues like that. Even if you'd reach that point where you're satisfied and you release, 100 people will use it in 99 ways that you didn't foresee. Some bugs will still be there, some icon forgotten, etc. Users at this forum know that roms are never finished, in fact they seem to even crave updates (even if a rom is "perfect", like CM10.1 supporting nearly everything possible of the original and still people want more). Just know that people here would be fine with having an unfinished version to play around with while you finish the rest.
I don't want to push you to release an unfinished version of your work, you take all the time you need. It's a hobby anyway, you do this for yourself in the first place.
EDIT: I also have a suggestion about the e-mail app. Since you don't use it, maybe you could just include an existing app and save yourself the effort? Not warez but a free one and ask the dev. There's a Google+ group for Holo apps: https://plus.google.com/communities/112110996671697454680, since you aim for a Holo look in your rom.
I thought this mail app looks quite Holo: https://play.google.com/store/apps/details?id=com.maildroid&feature=md. It's not exactly the ICS/JB app, but frankly Google doesn't even comply to Holo in a lot of their own apps. So if you want continuity, better a non-Google Holo app than a Google app that doesn't even follow their own guidelines, right?
Yeah Chrome is kinda laggy on my Sony Xperia S. I prefer the stock browser or Firefox, but I keep Chrome around for syncing bookmarks (which stock browser apparently doesn't do, must be a Sony thing). It's not that Chrome is slow, hard to put my finger on it, it's just not fluent.
Oh and I totally disagree with the OP. For starters there are nearly perfectly working JB roms that you can tweak as much as you want. Once a new version of Android comes around, I bet it won't take 2 weeks before tilal or someone will have a "working" alpha of it for Skate.The only things not working at this point in JB are the camera flash and FM radio (but that was a CM thing, I know CM started supporting FM on my SXS only a few months ago). Both are things I don't miss, with TuneIn radio I'm not as dependent on the FM signal (yeah I have a big data plan so I can use it as much as I like) and the camera flash was crap to start with. Might be that GB has the most performance, but what games can you still play on armv6... I'll admit that some people might like GB more than later versions (I like Android 4.1 more than 4.2), and I'm quite curious about H3ROS's project, but most other GB roms just try to be ICS or JB without being able to.
The Sony keyboard has swipe input. At least it does on my Xperia S and I'm using the same app from the Z firmware. Good thing about Sony is that many apps get ported across all of their (older) devices. Well their update cycle sucks, but had to say one good thing :P.
It's not like ZTE is so much more trustworthy than Newman etc. They're equally Chinese. Only problem you'll likely face is a lack of updates because of the Mediatek chip. That's why I'd suggest getting something with a Qualcomm. They also drop support but not as quickly. Feeling kinda stupid that my Xperia S (with Snapdragon S3) is most likely not getting an official update to 4.2.2. Same story as with armv6 all over again. I should've bought something with a Krait but at the time the only phone in Belgium with Krait was the HTC One S. At least Sony has learned by now not to use soc's that are a year old.