why not check?
from the terminal, as is typical for unix, i get up to 255. the finder also let me enter 255. seems true for ufs or hfs+.
on an aside. this is super funky to me.
HFS+
moxie% rm -f lowercase LOWERCASE
moxie% echo test > lowercase
moxie% touch LOWERCASE
moxie% cat LOWERCASE
test
moxie%
UFS
moxie% rm -f lowercase LOWERCASE
moxie% echo test > lowercase
moxie% touch LOWERCASE
moxie% cat LOWERCASE
moxie%
sure am i glad i formatted UFS. as a UNIX guy that would have driven me insane.