Dell don't make any PDA's. Their current AXIM range is manufactured by Wistron.
Now, if you were to ask why Dell don't resell PDA phones, I'd guess that it doesn't really fit with their business model.
Smartphone enthusiast since the Nokia N9000i; owned almost everything since
Current Android Devices: Advent Vega, Dell Streak, HTC Desire, Samsung Galaxy S2
Current iOS Devices: iPad, iPhone 4