I've been collecting old seegar boxes for just this purpose. The old ones are made of solid wood and are generally made a little lighter (sawry 'bout that pun) than the newer plywood examples. It probably doesn't really make a great deal of difference at this level, but who knows. I guess I could try both as there seems to be many more plywood examples that I seem to run into these days at garage sales where I hunt them. I don't know that I'd try to build a guitar, as the boxes I've found seem kind of small for a guitar body, but I was thinking that they'd be just the right size to use to make a ukulele. That's my plan and I'm stickin' to it. Okay, maybe a banjo uke or even a fiddle would be a hoot to make. I don't know that this is one of those project ideas that are real high on my to do list, but one of these days in the not too distant future look out.