I can point you at a start.
www.proclipusa.com has IMHO the best mounting concept around. The mounts come in two parts. A part specifically designed for YOUR vehicle, and a part designed for your device. In this case they only appear to have a Zune 30 cradle at this point, without any charging/etc. features. I have however used their vehicle side in conjunction with other manufacturers device mounts (Arkon to be specific) to create a great solid mount for my PPCs.
If you've found some cradles to your liking, very possibly they can be adapted to fit the proclip mount.