If Mother 3 is coming out at all, it's coming out for GBA. The commercial for Mother 1 + 2 had 'the blurb' about a Mother 3 for GBA, and Shigeru Miyamoto said in a November '04 interview that Mother 3 will be released for the GBA sometime in late 2005.

We've seen no media from the GBA Mother 3, though. It's unknown wether they'll hit us with a big shocker soon, or if they gave up.

And yes, I like Earthbound. The Starmen.net forums are the only other forums I visit.