There is a 'water transer decal' paper avaliable for your ink jet printer. People have bween pushing / talking about that... But for a large size, you'll have to use multiple sheets.

You might want to look at vinyl lettering. Most are cut with a cutter connected to a computer, and most should be able to read a raster based file. Look in the yellow pages under 'sign makers'.

There was a site that specialized in custom lttering for the RC world, but the name escapes me.. Custom lettering.com.. something like that.. They had a banner on the old RCO site..

Give Bill Fulmer a shout. He does a lot of this sutff. Met him once - very nice guy. Had a bunch of stuff on display.
I have only heard good things about him.

http://www customcutgrafix com/

Dan