-- Edit: forget it, I'll just answer your question again.
No, there were no other parties involved or interested with the conversion of WoWAce. Kaelten, the owner and administrator of WoWAce, is also a Curse employee. I believe (and he can correct me on this) that after the hosting bills for the old WoWAce started to pile up he sought assistance in hosting the increasingly popular site. This help came from his employer because they were already an addon distribution method and had the infrastructure to hold the old WoWAce together.
However, the bandwith used by WoWAce continued to grow. It grew beyond the means Curse could provide for free, so Kaelten decided it was in the best interest of the Community to officially merge WoWAce into the Curse Network.