Update: I'm now using the Clevetura CLVX S keyboard, and I highly recommend it, especially to BTT users. Though the keyboard does not have BTT integration, it does allow for setting up or triggering custom shortcuts using finger gestures on the keyboard. Of course, I wouldn't be surprised if Andreas could add BTT integration if enough people were using the keyboard. I've used an Apple keyboard and Magic Trackpad for a long time, but the Clevetura CLVX makes the Apple software pretty useless at this point. I highly recommend checking out the keyboard. There are plenty of videos on YouTube showing how it works.
I just learned about this keyboard, which includes the ability to do swipe gestures on the keyboard. I'm wondering if anyone is using the keyboard with BetterTouchTool?