This sounds absolutely awesome and I hope you do write it!
I think you can go a number of ways... A lot of the movie's plot does revolve around het and sexism, but I think classism is also a huge part of it, and Draco could absolutely find himself forced to marry a rich heiress because his family's finances are going down, right?
I would love to read genderbending too, though, so I say just go with whatever feels best to you. I really think you can write it without genderbending if you wish to, with homosexuality being an issue. I can see it, it would make for a great fic!