I would definitely get a boaphile. Those tubs are a pain in the butt to say the least, and are just not secure enough for a strong boa. Plus they are ugly as anything.

You *may* be able to keep a male bci in a 4' cage. If he passes 8', you're going to want a 6' cage. If you really want a smaller boa, go for something like a hog island boa.

As long as you are responsible, there is no reason not to keep a boa when you have a human baby around.