Considering a RTB... advice?

I agree. Go with a dwarf Boa. Some are even smaller than hog islands, such as Tahamara Crawl Cay and Cay Caulker. Even for a "large" female, a 4x2x2 would be more than enough cage.

Here is a Picture of my Hypo RTB
I bought him November 2009 when he was only a couple months old ....http://i1000.photobucket.com/albums/...poleock/09.jpg

Here is a few Recent Pictures ONE year later....
http://i1000.photobucket.com/albums/...k/IMG_0580.jpghttp://i1000.photobucket.com/albums/...k/IMG_0579.jpg

Another Boa that stays relatively smaller is a Hog Island Boa .. Here are some Pics of mine .. He is an 08(I think) He is my FAVORITE Pet, Snake, Reptile Hands down.
http://i1000.photobucket.com/albums/...k/IMG_0583.jpg
http://i1000.photobucket.com/albums/...k/IMG_0587.jpghttp://i1000.photobucket.com/albums/...k/IMG_0585.jpg