Zak: Both Adrian and I went to a small school with only a moderate Greek presence, so there are a lot of fraternities we don’t have any experience with or know about. Both of us were encouraged to rush different frats at different times by guys who knew that we were trans*, with some of them mentioning that even though it was against the rules of the national organization, they would be okay with overlooking that. Because of that, we do know that some fraternities have it in their national by-laws that members have to have been born male (this is the case for Alpha Tau Omega for sure, probably some others too). Some chapters might still be cool with letting you rush, though, while others might be more concerned the potential repercussions of breaking that rule. If you are stealth, you also could probably rush without being concerned about those rules. So, you can start by reading up on the different frats and seeing what, if any, kind of rules they have regarding trans* guys.
I don’t know of any specific fraternities (other than Alpha Omega Nu) that have a reputation of being particularly open to trans* guys, and frats vary a lot school by school, though, and so I think the best thing to do is feel out the specific guys at the chapters you’re looking to join. I do know of a couple of trans* guys who have rushed and been very happy fitting into a Greek organization, but the main thing that made it a positive experience for them was that they liked the specific guys in the organization that they joined.