Don't know about the USA but I know they're available in Canada. I have a Fat Integra in Vernon BC. Fun bike. My only issue was with the battery connection but I've decided a few seconds on the end of a winter ride is liveable, If I'm going riding I already have the tool on me so no big.
I've only ridden it in the snow but it rides really nice, it is quick and responsive. Tons of power from the Brose Drive, I mostly left it in the lowest assist level (4 available). It came with Schwalbe Jumbo Jim 26x4.0 tires but has room for probably up to 5". Jumbo Jim kinda meh but better than many.