That's what I did/am doing!
As you said above, if there is ANY chance this can be done, I am going for it. Registering means I at least have my spot if it works out. It is worth the fee for me.
I'll have to carry my 5K medallion with me on the 10K too. No biggie, I'll just put it in my belt.
Oh and some people on fb (or at least one person, can't remember) has been in contact directly with runDisney about this topic. I guess as of now there are no plans to change any times, but they aren't saying you aren't allowed to do both. Until I hear that they will not let people do both then I am keeping my mind open to the possibility of it working out.