I've been using SBCL with a copy of SLIME that I checked out on March 4. I was quite happy to see that when I evaluated
(setf (readtable-case *readtable*) :invert)
SLIME didn't die. However, there are some weird bits, especially symbol completion, which seems to work for oneword symbols, but not multi-word-symbols. I've slowly come to the realization that I'm one of only a few Lispers who regularly works with case-inverted readtables, so I'm guessing not much thought has been put into this question. For you all who know the insides of SLIME, I'm wondering if it would be much work to get SLIME to be inverted-case freindly, or if a couple well-placed WITH-STANDARD-IO-SYNTAX's would do it.
[ A 5-second summary of inverted readtable-case, in case you were headed for the CLHS:
(setf (readtable-case *readtable*) :invert) (string 'foo) => "FOO" (string 'FOO) => "foo" (string 'Foo) => "Foo" ]