I'm ordering a set from Tony [http://www.tonysforendsandgrips.net/] and he asked me to verify some dimensions for the forend. I got out the calipers, and well I figured I'd post it here in case anyone else found it useful.
Here are some measurements, starting where the frame ends moving forward to the muzzle. Measured using a Franklin Arsenal digital caliper so the caliper could slide snugly, in other words not gripping at the point of measure. Temperature is about 70.
.805", where the frame ends (measured while attached to frame)
.782", immediately behind the rear forend stud, but not on the stud base
.772:, immediately forward of the rear forend stud, but not on the stud base
[3 9/16" between stud centers]
.748", immediately behind the front forend stud, but not on the stud base
.742", immediately forward of the front forend stud, but not on the stud base [13 11/16" from muzzle]
.730", 1 1/16" forward of last measurement, 6" forward of frame
.722", 7" forward of frame
.712", 8" forward of frame
.703", 9" forward of frame
.695", 10" forward of frame
.688", 11" forward of frame
.680", 12" forward of frame
.673", 13" forward of frame
.666", 14" forward of frame
.658", 15" forward of muzzle
.651", 16' forward of muzzle
.649", immediately behind front sight [16 7/16" from frame, 2 3/8" from muzzle]
.629", muzzle