nabla: I think cubed matches are treated the same way as multi-game matches in other games. And there a time-out only times out a single game.

But I agree, it would be nice if you can offer a resignation for a certain amount of points. For the user interface, only three options need to be offered "resign with backgammon", "resign with gammon" and "resign". If a backgammon, or a gammon is not possible, those options don't need to be offered. And an opponents confirmation is only required if the choosen resignation isn't the highest possible.

Separately, it would be nice to have the option to resign the entire match - not just for backgammon, but for all games.