Not a full-scale butcher, but the meat counter at Bari (which is close to downtown or downtown, depending on your definition) typically has a good selection, good prices and they will cut to order. Hours are somewhat short on weekdays for working folk of the 9 to 5ish variety (they close at 6:00 and the "back" ostensibly closes at 5:30, but I've been served between 5:30 and 6:00), but you can call your order in and pick it up fully packaged and ready to go.
Butcher counter at Bari is also discussed in
this LTH thread
Bari Foods
1120 W Grand Ave
(312) 666-0730