Compile Farms for Commercial Software?

unix-coder asks: "How can a small software company get to 'rent' accounts for short times on a wide range of machines running different commercial Unixes with different CPUs? SourceForge's compiler farms are great for open source projects (and besides, open source projects will get ported/tested/fixed on all the platforms that matter to the people that use them). But what about commercial projects where you want to port/build/test for a wide range of architectures and OSes (AIX, HP-UX, IRIX, ...) but don't want your several server rooms full of weird hardware of your own?"