If you are thinking of getting a Gear Vendors OD, that trans will give you the shorty 727 version. It will shorten the overall length by the difference between it and a regular 727.

It will likely have the HD internals but my understanding on the 4 pin planetaries is they aren't any stronger because the aluminum spline fails long before the pinions do.

One of the 727 gurus here can speak to whether the drums can hold more clutches than a regular 727.

Kevin