It's not totally crazy. I think Meebo's mostly written in C++, for instance, since they're always looking for C++ and JavaScript people but they never mention scripting in their job ads: http://www.meebo.com/jobs/openings/server/ I think they mention in one of these blog posts that they wrote a lighttpd module.

I've written a C++ Apache module for a simple web app before. It's definitely harder than using a scripting framework though, not so much because of the language, but more that frameworks have functions that help you do just about anything (e.g. sanitize input, construct safe SQL). In C++ land you're more on your own since most people aren't crazy enough to build a web app in C++.

Also, if you go down this route and you're particular about C vs. C++, check out mod_cpp for building Apache modules: http://sourceforge.net/projects/modcpp/

I echo the advice that if you have something performance-sensitive, build it in C/C++, but proxy it through something built with a better-known framework. Thrift is great for this: http://incubator.apache.org/thrift/