Ok ok ! Personally I think it is safer to split the project in several panels
! Anyway, try the software Cstitch_0.9.6, I use it myself and it has no apparent limitations (I once tried the same pattern as yours, by curiosity. There was no problem at all).
Concerning the aïda, I once find a piece of fabric really large, but it was in carpet store (between 1.5 and 2 m thick I guess).
Anyway, good luck for this masterpiece !!!!! (I can't wait to see the results !)