Something like this? I have no personal experience with tracks, but these look like they should be very smooth. Plus you switch from tires to tracks or back to tires when you want. They should turn better and probably leave less of a berm. I have seen these in video and the tracks do split open in the middle to adjust to the terrain making them even smoother than regular tracks.

 Here's a link to their web site. It's not much, but you'll get the idea.

http://www.soucy-group.com/english/whatsnew/whatsnewarticle.asp?h=1&ID=23

(Soucy tracks (Large).jpg)

Soucy tracks (Large).jpg (111KB - 200 downloads)