Hello all. I've been doing some tinkering, and now have a Rails installer for XAMPP on Linux (Ubuntu Hoary in my case). It basically compiles Ruby, Gem, FastCGI (including changes to the Apache configuration file), Ruby bindings for FastCGI, Ruby MySQL integration, installs Rails and its dependencies, Rake and RedCloth, all into the /opt/lampp directory. I've also made a couple of patches to Rails source files to localise it to XAMPP (e.g. so the generators find the MySQL socket, and so FastCGI is used by default), and added an automatically generated sample application (simple email directory) with XAMPP styling
I haven't thoroughly tested every nook and cranny yet, and haven't made it publicly palatable (e.g. I haven't tracked all the dependencies for doing the compilation, and I'm not sure what all the Ruby configure flags do), but if anyone is interested, you're welcome to my script. Collaborators are welcomed. I'd like to see Rails integrated fully into XAMPP (though I'm not sure if I'm the person to do it), so that there's a one-click installer for it comparable to the ones available on Windows and Mac. XAMPP seems like a good base for an effort like this. Whatever, I'm going to find it pretty useful!