On the DS1, it's more complicated and it will require a daughterboard. It's because the DS-1's chip is a dual, single-inline design. AFAIK, only analogman and myself are able to put in dual op-amp chips on DS-1's . But it's not hard naman, I'm sure there are others who have cracked it that I just havent heard about.
For the BD2, pwede din lagyan ng FET-input chip. IMHO tho as my OD100 sho ws, the tone differential won't be as dramatic as, say, on a TS9 because on the BD2 (and the OD100), the op-amp chip is situated after the main transistorized gain stages as well as the clip stage. But yes, there is still an improvement.
Other pedals, like the MT2...still infeasible to replace the chip (in my capabilities anyway). It's not impossible, I just haven't given it the proper study and design that's required