I have the 2730 (same size as 2720). For the first month I used the beanbag mount on top of the driver's side dash, but this dash is so smooth, it doesn't hold the bag mount very much.
For some reason I don't have any good pics handy, but I have it permanently mounted towards the front of the driver's side speaker. You can see it in this pic behind the inspection stickers.
If you want, I'll grab a pic for you tonight.