As much as we all want Rory and Luke to get together, I don't think it's gonna happen. I mean, think about it.... If Rory and Luke were to develop a relationship, it's pretty much inevitable that it wouldn't last. After all, they're kids and they don't really know what they're doing. If I were Dom, the friendship they've developed (which could potentially last a lifetime) would be far more important to me than a year long "boyfriend-boyfriend" thing that would probably end in a fight. But maybe anything's possible. Maybe they'd make it last. But I doubt Eddie and Jase would be thrilled about it either. But hey, maybe Dom has that in mind in order to create more drama
Besides, I've really taken to Seth anyway. He seems much more like a 'man' then Luke. And Rory needs that influence to provide some stability in his life. Luke still has a lot of growing up to do. I dunno... he seems like too much of a kid still. Even though he can be very emotionally mature with Rory at times, he just doesn't seem to have a lot of structure in his life. Maybe that's why Rory hasn't really developed any emotional feelings for him (that we know of ), other than a physical attraction. On some level, he needs someone with his feet on the ground, that's why he's falling for Seth.