Yes, that's the right name (the flowers appear in pairs). Should be relatively available, at least compared to some of the other smaller agaves. It's probably better than average at dealing with excess water as it comes from a relatively wet habitat, if I remember right.
Agave "Kissho Kan" and its variegated cousin are excellent candidates for a smaller space. They will offset but not out of control. Probably cold sensitive but no more so than attenuata, I would imagine. Not an issue here.
Agave "Cream Spike" will take a while to get big, especially when constrained in a container. You want to start with a solitary plant that's a gallon size or bigger (say 8" diameter or so) as the smaller ones go through a phase where they offset like crazy... this tends to abate once the plant transitions to its adult (erect) phase.
Agave "Bloodspot" is a very pretty smaller plant that's similar in shape to macroacantha, but tends not to get as big or offset as much. (A. macroacantha is a very nice smaller plant but it does tend to grow in clumps and the spines are serious enough to make that difficult to sort out if you let it go.)
Agave colorata comes in various sizes but the more common form around here is relatively small and might work for you. It's a nice chunky plant.
There are a few smaller agaves which I would not recommend (esp. in a wet situation). A. utahensis is a very pretty plant but can be a bit tricky in cultivation (water sensitive).
If you would like to see pictures of any of the above I can rummage around to see what I've got.
