The other tablets I have looked at were not up to it, but the Nexus seems just right.
Apart from the Nexus the total costs were £11.99 for a Bluetooth OBDII Plugin adaptor, £3.99 for a cheap Dashboard Mount, & £2.49 fo rthe Torque Pro App (Paid with my Google Credit).
Here are a few photos and Videos of it in use.
The OBDII Adaptor
The Adaptor Fitted
The Dashboard Mount
The Nexus Fired Up
A Youtube Video of it in use
Still loads to learn and configure, but a great cheap add on to the Nexus along with SatNav.