You'd have to get original fix from torrents maybe - I can't do that. Found InDigo176 source code and aclair recompiled it. Source included for posterity. http://www.2shared.com/file/mppBwX5u/rc2_bump.html
I got a hold of Rollcage Extreme (unofficial Rollcage Stage 2 for modern hardware) and it is superb. I believe it has the bumpmap fix built in, but I could be mistaken (no bumpmap option in the launcher). It also supports 1080p and new widescreen resolutions.