Microsoft Natural Keyboard Elite
Model number is E06401COMB. Sounds like Key Tronic. They definitely made the older model (simply "Natural Keyboard") and it would explain the relatively stiff but tight domes.
I'm using it mainly because I'm at my dad's place, but haven't brought my usual travel keyboard. This layout drives me mad. 6 on the wrong side (heh) combined with a weird-feeling offset due to the split, and I'm lazy to remap the whole number row for only a day of typing. I'd also get rid of the numpad or nav section. So yeah, I basically want the more recent Sculpt Ergonomic keyboard. I do have one at home, but still never use it, because of the annoying wireless implementation.