- Move either EchoStar 6 or 8 to 129 (which would drastically reduce service in Eastern Arc, so it is unlikely)
- Move EchoStar 1 to 129. It is not far away, and Dish has been aggressively moving channels off EchoStar 1 over the past few months.
- Buy or rent someone else's satellite, either in orbit or about to be launched.
If I had to bet, I would bet on moving EchoStar 1 as it would likely last long enough, i.e. until E*6 or E*8 is replaced by the new satellites slated for 72.5 and 77, and then one of those could move to 129. Remaming E*1 channels could move to 110, where there is currently free space, as well as PPV channels that could be temporarily removed.
I would suspect that some delays in launching on new channel additions have been due to E*'s lack of backup right at the moment - they may be waiting for successful launch and test of Ciel-2 which would give them some breathing space.