Very unlikely. If they ever got together, i doubt it would last long enough, and if it did, niether are sentimental enough to propose.
Although Heero was the one to confront Wufei in EW, and Wufei said something along the lines of "i've been waiting for this moment," i really think that is very far from a hint. In fact, it may be a hint in the opposite direction. They never seem to really click in any way at all, and avoid eachother at all costs. Heero seems to be the natural leader, and Wufei wants to be alone, under his own rule. Not any likely hints here.
It wouldn't work out. They would get into lots of fights, and probably one would end up dead. (Heero does hide that gun in some unlikely places...). i dont know, maybe i'm biased cause i like Wufei and not Heero, but i really doubt that they would last. I dont think that they would even have feelings for eachother unless they were trapped in a room together for a week with unlimited supplies of extasy and/or beer.