Heero and Trowa
This is the second most popular pairing for Trowa, there are plenty of hints (though not as much as 4x3) within the series, and the two seem like they would work very good together. It doesn't seem likely that there was any kind of action going on within the series timeframe, Heero's efforts to be detached seem to show that he wasn't really 'with' anybody during the series (and if he was, the relationship wasn't successful) but the way two mesh together so well leave many fans dreaming of a chance meeting a few years after the war.
Trowa is, to say the least, impressed by Heero, even going so far as to say "everything he does is perfect." Heh, sounds like a school-girl crush to me. The admiration doesn't seem to diminish as the series goes on, Trowa reveals himself as quite willing to go along with whatever Heero wants. It doesn't seem completely one-sided either. Heero is more open to Trowa and even a bit protective of the taller pilot. The time they spent together after Heero's attempt to self-destruct must have at least made them friends, perhaps making Trowa closer to Heero than even Duo could get.
Would they ride of into the sunset? Yeah, I think so, if both of them got over their emotional hang-ups (and Quatre was out of the picture) I see it happening. Would they live happily ever after? Who knows, but it doesn't seem farfetched. They'd get along very well I think. They're both so soft-spoken that I don't see too many personality clashes arising, and they seem to trust each other enough to open up to each other. I don't know how Heero would handle Trowa's emotional pain, but I don't see him bailing out because "it's too heavy," you know? One possible conflict that could arise is the fact they themselves would have to take the initiative to take down the barriers they put between themselves and others. Catherine and Quatre were surely good experiences in caring for Trowa, and Heero was a lot more open by the end of the series, so even that possible problem isn't a magor concern.
I like 1x3, not as much as 4x3, but I think they would be very good for each other. It's actually a very sweet pairing, despite the stoicism of the two. I'd like to see a little more attention given to these two actually, this pairing, despite being so well-matched, and rather plausible seems to get overlooked quite a bit.
Goodies?
Sorry folks, no pics, fics, or links quite yet, but there will be, I promise.