Check out Bicycle Bill in Allston and A-1 (I think that's the name...) on Elm between Davis and Porter. They're both staffed with off-duty couriers who can point you to the exact thing you need. They should be able to make any modifications to the bike before it leaves the store. A better shop should be willing to switch out grip shifts (if they were there) and hook you up with baldies with no charge.

BB knocks the price down on late models too, so you might be able to get something decent if you don't mind not having this month's gear set.