This looks pretty nice; would be interested in checking one out.
I LOVE the boosted throttle as well; was a real breath of fresh air.
RION is also offering something similar, the
curve but it's quite expensive.
I've also bought the throttle unit directly and 3d printed an enclosure to get the same thing at about $100.
Last; there's at least one half-twist out there (which I also have, lol toys) which has a dual spring setup and does the same kind of "idle to 2.5 position" trick for being used in accel/regen single interface. I think the per unit on that was <$25.
All of these options, baring the last one (and it being a different form factor), are hard to justify for the cost. Grin's already shown the ease of which "when brake lever pulled, throttle is now regen" works as a really nice, no extra cost, any-hall-can-be-used solution. I hope your offering is more completive with the rest of the throttle market.