I'll try for a third time to post these for anyone still interested in some of the comparitive differences and similarities between the BFRs and the Blackhawks.
Here is a shot of the trigger guard and lower frames of the two. The BFR is 0.930" in width while the Blackhawk is 0.740," these measuremnets taken at the forward portion of the trigger guard.

The narrow "web" at the front of the frame - it probably has a name, unbeknownst to me. The BFR is "0.340" in thickness, the BH 0.290" thick. The cylinders are 1.885" and 1.730" in diameter respectively.

The grips; the Blackhawk wears a Pachmayr product while the BFR came with the similar grip made by Uncle Mike's, I believe.

The BFR's weak point may be here at the rear sight cutout. As massive as the rest of the frame is, it is considerabley thinner and possibly weaker than the Blackhawk here:

The BFR measures 0.210," the Blackhawk, 0.310" at the narrowest point in the frame beneath the sight. If this is indeed the weakest point in the frame then the extra mass in the rest of the frame serves only as ballast, an admittedly not necessarily unneeded thing, but one not always desirable either.