There will likely be a XM and Zaon update to add these function to the iFly sometime next year. We already have the development docs for the Zaon and Walter is digging into the XM side of it. It should be a faster process due to much of the rendering and such being completed with ADS-B.
There will almost for sure be additional devices on the market by 2013. The FAA is encouraging ADS-B development amoung manufactures. This will fuel features and competitive prices. It's currently a hard call and truely different for each individual's wants or needs. I hope this helps.