After trying out Winbench '99 without too much success, (http://www.winehq.org/pipermail/wine-devel/2006-December/052818.html), I managed to buy a copy of Winbench '96 on ebay for $3 or so. It seems a little closer to running -- the things that stop it appear to be more garden variety problems, not whacky COM stuff.
While there aren't any more copies on ebay, I discovered that searching http://froogle.com for winbench found three books that come with a copy of the tool:
"Using Windows 95 : Platinum Edition" (0789707977) comes with Winbench '96
"Optimizing Windows 95 & Windows NT 4.0" ( 0789708418) comes with Winbench '97
"Tom's Hardware Guide" (0789716860) comes with an unspecified version, maybe '99 (which is downloadable anyway, so maybe that's not so interesting).
I guess I'll pick up a copy of that one that comes with Winbench '97 just for completeness... - Dan