I am was a 14C when i first got pregnant and went up to an F whe my milk came in. Unfortunately I didnt end up breast feeding but my bb's have only come down to a DD. While DH isnt complaining - he isnt the one that needs to find bras that fit!
Anyway - I know they aren;t maternity bras but I found some fairly inexpensive underwire free bras from best and less - everyday woman or something along those lines. I guess you really only need the "maternity" part of the bra when you are feeding bubs. But don't quote me on that. They are not beautiful bras or antying but now i settle for function instead of pretty bras.
anyway - my 2 cents.