I am trying to do a very similar thing. I want to put a dark red from hirsutum with a (B) beta -carotene and (gf) green flesh in a meaty heart tomato for a super dark orange heart with extra carotenoids. I've read a lot about (dg) which is an allele of the hp-2 gene and seems to have a lot of negative effects too.
http://tgc.ifas.ufl.edu/vol36/v36p10a.html - here is something of interest on (dg). Another thing that is very interesting is a tomato from I think the 1950's called Black Queen (Webb Special) which has hp-1 and hp-2 but I could not find anyone who has it.
craig