Wasn't going to say anything, but keeping silent and fading away didn't really sit well with me. xD
I'm personally in the "Write Only" camp, though I think it might be best for me to withdraw completely.
I don't mean to question your ability as a GM, but running two different systems would be like running two separate RP's. And I'm sure we all understand how difficult running one RP can be (nevermind two).
Essentially I just keep thinking down the lines of "He who chases two rabbits, catches neither." And it makes me feel a bit uneasy.
Thanks for the offer, and best of luck with the RP, but I think I'll be sitting this one out.