The more I think about this, the more I love it. I'm not 100% sold on the offset arrow keys, but that's more a personal preference. Full numpad on a compact board is a huge win.
I'd almost like to see the backslash and backspace keys switched though. I know it's unorthodox, but in a compact keyboard I think I prefer the backspace to be with the alpha keys. The 2U key in the number row could be changed to 2 x 1U keys to have the backslash and hyphen keys with the number row. In saying that, I don't often use backslash so I don't know how inconvenient it would be if it were in the number row.
Love the idea of Bluetooth too eventually. I hope this goes well, definitely interested in seeing the prototype.