Modems are pretty much at the end of the road as far as development goes.
Barring some extraordinary discovery, I doubt manufacturers will be investing any development money towards future protocols.
Assuming you don't have access to cable modems/DSL in your area, your best recourse would be to start calling/writing your local phone & cable companies to push for broadband access in your area. You might also look into one of the new 2-way broadband satellite dish services on the horizon.
Good luck!