Not sure if i should post here (this thread is almost 8 years old!), but sbcl works on OS2008 (and should work on other maemos as well).
I've tried the precompiled 1.2.7 armel binary on an N810, and so far seems to work. I still haven't tested it extensively, but all the ANSI stuff i've tried works as expected.
As soon as i can use my N810 again i'll test more stuff, sbcl-specific things and maybe external libraries as well.
The REPL isn't really a pleasure to use, so i might try to get rlwrap to work (not really important though).

Maybe useful links:
http://www.sbcl.org/platform-table.html
http://www.sbcl.org/getting.html
http://www.sbcl.org/porting.html