What should my next snake be... Suggestions?

[awwalz01]

So it won't be anytime too soon, BUT as I am sure some of you know, it is hard to halt your brain. I want something a little different. I have one slot left in my rack that is set up for a hot spot of about 90 (currently set up for my carpet python until he gets too big for the rack). It is a 41q boaphile ball room rack. I want a snake that is suitable for those temps and would like it to stay small enough to be able to stay in a 41q rack for its entire life.

I know that is somewhat restrictive criteria, but what do you all have in mind?? Just trying to bounce ideas around in my head so I can decide what I want and do research on the species that I decide to go with.

So to recap:
1. 41q rack max size
2. 90 degreeish hot spot
3. Something somewhat different than the super common species
4. Do not care if it is a python, colubrid, boa

Thanks in advance!