Make it available in 20 gauge, and I'll buy one. I think 12 gauge recoil in a weapon that short would be a bitch to control well. I think the higher number of shots more than offsets the smaller gauge.
In 20, this could be a superb home defense choice for women.
FWIW, there are lower-recoil 12-gauge loads that are suited to home defense. The Aguila 1 3/4" Mini 12-ga shotgun shells are one such example. Aguila's "Minibuck" shot loads are stuffed with 7 pellets of No. 4 Buck and 4 pellets of No. 1 Buck at 1200 fps. Not all repeating shotgun designs feed the stubby little things well, but it's an option that should be explored if recoil is an issue.
Also, are not standard 20-gauge shells the same length (2-3/4", minimum) as 12-gauge? The Aguila minis might add one shot to the tube, but in general, 12s and 20s load the same.