And not being able to run Build.PL due to missing Module::Build at all is an advantage right now why?
There is the Vanilla/Strawberry Perl initiative which caters for the people who don't have Visual C and the corresponding make tool, and so far I think that's the better approach than waiting for 5.10 becoming so widespread that using Module::Build becomes a viable path.
Another very good option is Module::Install, which even tells the user where/how to download and install nmake if it's not found. Which EU:MM could do as well, but ...