NITDroid Alpha 3 for N9 has just been released. Once it reaches beta an N9 may be the solution for you. You can boot into ICS for the occasional Android app while using MeeGo as your main OS.

An N900 may not be the wisest choice. The N9 may be declared DOA but at least it is still in production and still being upgraded. It has more useful life left than the N900.