737jock, if I understand your post, I think you haven't considered all the variables of configuration. In particular, flap changes Vs a lot but doesn't change Vmc much.
The tailfin may be perfectly sized for controlling the aircraft for an asymmetric go around with landing flap at minimum weight - that is, in a combination of circumstances giving a very low stall speed with a moderate to high Vmc.
But in that case, Vmc will be very much lower than required (for certification) in clean or take-off configurations. It could well be below Vs.
If I've misunderstood your post, my apologies!