Hi, didn't notice your post on the boa forum...sorry!
Any of the island species can easily stay small. Stay away from BCC if you want smaller. A lot of size is genetic but also a lot is how much you feed them.
Forgive me, I never went the "tank" route, what is the floor size or area of a 80 Gallon tank? Basic rule of thumb is 1 square foot of floor per foot of snake. Can go a bit smaller than that and of course the sky's the limit on larger.
To further help, what do you want in a boa? So far you've only indicated you want smaller. Maybe a Brazilian Rainbow Boa would also fill you want/desire for a boa? They are typically around 6 feet and while muscular like a boa are nowhere near as girthy. Kind of like a corn snake on steroids 
>>well, i posted this on the boa forum and got no replies. they are to busy showing off their boas to help someone interested in a boa. can someone help here??
>>
>>hello. can someone tell me which are the smaller boas. i know some get to like 10 foot and thick. that is to big for me. i was looking at hog island boas but is there another one. i'm looking at keeping it in a 80 gallon tank when its big enough. right now i have a 7-8 foot JCP in there and want to move him to something taller. so eventually i'd like to house a boa in the 80 gallon tank.
>>thanks.
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Thanks,
Dave Colling
www.rainbows-r-us-reptiles.com
0.1 Wife (WC)
0.2 kids (CBB, selectively bred from good stock)
LOL, to many snakes to list, last count:
13.26 BRB
11.16 BCI
And those are only the breeders 
lots.lots.lots feeder mice and rats
