From what the bros here say ( i haven't heard the RE0s before) you are not going to find something with the clairty the RE0 with more bass without having to fork out much more.
I think some EQing might be in order. Or go for other earphones with more bass presence like the NE6/7, Eternas (might be too much though) or the Meelec M11+.
IMO your best choice is to buy a bass amp and do some EQing. You save quite a bit plus you get the use the amp on other earphones in the future