I used to work in publishing and film so I got to know a thing or two about how rights work and how businesses handle such things.
If you want another publisher (and I mean a more major one, not some small "fly by night" operation - though I'm working on starting one of those myself myself

) to publish your work, you will have to sign the rights away, most likely. If you are looking for a small press to go with you may get lucky. I'd be willing to bet many of them either don't know the right way to do these things, don't have the money to pay an advance and so will make other arrangements as compensation, or are simply so keen to get decent product out under their lable they'd be willing to make all sorts of unusual deals. Bigger presses are probably turning people away, so they can dictate their terms - it would make no sense for them to not acquire rights to something they think have value - thats where there's an annuity in the future, especially if the publication proves to be successful. That being said, you are most likely to get more real money from a big press as an advance they you will ever see from a small press - small companies seldom sell enough to make real money for themselves or you - but one never knows.
If you publish it yourself, you will control all the rights to non-OGL stuff, obviously, but self publishing is a whole other ball of wax and can get expensive, though with printing on demand, this business model becomes a far less expensive proposition then it once was. Promotion and your initial promotional stock (to send to stores, Chessex, etc. so they know you exist) becomes your major expense. Pdf publishing has very little expense save the personal investment in time (and maybe a layout person) to put the thing together, but you are not likely to sell very much either, so everyone says.