I've got my Nuvi 350 on the SW-Motech mount. Looks like this:
Yes I know the power adapter is ugly. I haven't had time to devise a new power cable for it. In fact, I haven't even tried the GPS on the road yet. Just installed it this weekend.
Here's what the mount looks like by itself:
I like the touratech mount too but this one looked like it would be more out of the way. The GPS sits to the right-hand side and I still have a view of the speedometer and odometer though the lower portion is slightly occluded.