http://naturalselections.safeshopper.com/51/541.htm?750 -Borneo Giant
Here's of pic of A.Borneo Giant. There is a guy who's trying to hybridize it with a hardy variety. Maybe the hybrid will work in zone 7-8 like others he has made.
His link is-
http://aroidiaresearch.org/whatsnew.htm He has some nice pics too.
Here's the absolute biggest Alocasia, but it doesn't do well in the US.-
http://www.wschowa.com/abrimaal/arac...ia/robusta.htm