that would be awesome, true, symbian isn't based on linux but i don't think thats a problem, i think the drivers should be close, plus if symbian^3 wwas ported on the n900 it will run in full speed on our overclocked devices (becasue everyone overclocked their phones, mine is running @900 mhz 24/7 ) .
anyway porting symbian s60 v5 is very posssible ( google it and u'll find the answer )
so symbian^3 is open source with qt based apps, so if symbian^3 wasn't ported most of its apps will be ported on the n900, now isn't thAT NICE, fifa10 on the n900, or nfs shift, or PES, or google MAPS, or shazam, or ovi maps 3.3, or a youtube client with hd videos support.....
now all what we should do is wait, i mean the n900 is just tooo damm good to drop it for an android or a symbian^3, if u want to get android get nitdroid, its full time os now.