You might want to check the Dom/Fetish section of BP

On occassion you might find a submissive posting there, I have seen Submissive X and a couple of others...whether they are into Daddy roleplay I couldn't tell you, but you will only find that out by asking...some girls might want a strict Daddy, some might want a nurturing Daddy, some might prefer a more perverted Daddy (my fave ) so make sure you know what kind of RP YOU want so you can tell her.

I know there is a Kandi (who's full name I cannot remember, sorry) who offers sumissive dark fantasies, she might fit the bill for you as well

K

Samantha (TER ID 239035) may also fit your bill. She especially gets into daddy/daughter RP, but seems to be up for almost anything. She is about six months preggo right now, but still is providing. I've had great RP sessions with her.