I don't think this is actually possible. Even if it's possible, then it must be hardly doable.

All in all your request is awkward: as long as the authors do include all the required files definining any macro they use there should be no problem processing the .tex sources. And I don't even know what you mean with "standard Tex file" - do you mean a single .tex source?

However if you are really dealing with (plain) TeX files, then I seem to remember a package called occam that may be close to what you want. Caveat: I don't really know anything about it since, in fact, I've never used plain TeX.

OTOH the fact that you talk about "class files" suggests that you may be using LaTeX instead. Then I don't know either how to do what you want nor why one could want to do so...

Whatever, I feel you may have more chances of getting a sensible answer on ctt. Oh, and did you check the (uk tug) faq?

BTW: since we're here discussing Perl and TeX, I take the floor to advertise PerlTeX which is very cool but unfortunately not widely known...