it has been a while since i posted last. that's what i get for letting things get out of hand around here. we've been pushing hard towards getting the first beta of visual studio 2005 (whidbey) ready and that has been taking most of my time. that plus the sunny weather we had for a few weeks. :)
there have been a few comments that i haven't responded to; sorry about that. let's see if i can quickly go over them now:
exothermicus was trying to get custom build steps to run a tool on all the files in a project using VC 6. if i understand correctly exo is setting a custom build step on every file. IIRC, this will override the tool that normally builds the file, so the compiler etc will no longer run. it's been a long long time since i used VC 6, but i'm pretty sure that is the behavior. that's certainly what you should get in VC 2002 and onward. an alternative may be to run the custom tool in a project-level custom build step. the downside is that you'll have to craft the custom build step to explicitly run on each file; there's no support for expanding macros to multiple items (e.g. $(AllFilesInProject)) or iterating over such items.
speaking of VC 2002, John-Mark was having some trouble with it. he was using a custom build step to generate .cpp files, but the .cpp files didn't seem to be getting added to the dependency graph. without more info i can't be certain what the problem there is, but make sure that the generated .cpp files are members of the project. John-Mark, if you have a simple repro project, or more detailed information, i'd be happy to take a look.
Chris was having the unfortunately all-too-common problem of rc files always rebuilding. Chris says the #ifdefs were removed, so the usual culprit of #includes of non-existent files inside #ifdef blocks isn't the issue... unfortunately there isn't any way to grok the dependency information. (Chris, you asked about reading the .idb, but the .idb doesn't have dependency information on rc files, just cpp files). this is one feature we want very badly to get into the product and never manage to. Chris, if you have a small sample project that repros the problem i could take a look and see if i can find out what's going on.

well, i'm out of time right now. next, back to the project system...