I don't know if you have seen it, but there are a number of giant scale foamies out there that are absolutely stunning.
1. Keith Sparks 1/4 scale P-40
2. 8 ft. B-17
(this ones been flown indoors)
3. a full (I think) scale Cri-Cri (also flown indoors) is in a video in the next link.
Several videos of all these in this thread http://www.rcgroups.com/forums/showthread.php?t=1607299
Just to name a few. However it does take some stick-to-it-ness to undertake such a project. Sure sounds like fun.