Gundam is tricky because the parade colors of the the RX-78-2 don't translate easily into a nice looking keycap set. There once was an officially licensed set that made it to group buy (I don't think it looked very good), but it unfortunately ended up turning into a dead project and most buyers lost their money. Because of that I don't think we'll be seeing another Gundam-themed set anytime soon.
You could try to mix and match different sets to build your own themed set, but that can become costly quickly. Personally, I got a few Gundam artisans and called it a day.