I started skimming the documentation, and I see that each app is kept in a seperate "sandbox" and accessing another apps regestry (understandable security feature). So writing an app to do some key fiddling to allow multiple apps wont work (outside of the app that is).
However, is there a reason that it would not be possible to load the same channel twice? Since each channel has it's own protected environment, it seems there should not be an issue of the duplicate channels behaving badly with each other. I would expect this would already be desired to allow new versions of channels to be tested along side current versions.
Only issue I can see is this would require possibly modifying the channel picture to identify which channel is linked to which account.
What I was really looking for was some way to get a second Netflix account attached to one box. Since I would not have the Netflix key, I don't think I would be able to write an app to swap tokens around inside the Netflix area within the guidelines of the API. (assuming the Netflix channel is even written under the same API and is not a totally separate executable).
Do you see any possible changes in the channel store down the road to allow the same app to be loaded twice?