I did try using MinGW for a while, but the build process for that seems even more broken than for Borland.

Actually, perl builds nicely with mingw32. I built the 5.8.0 several times using the mingw-gcc that comes with Dev-C++, when I didn't wanna wait for the ActiveState, and I didn't want to buy VC++ to be able to test embedding. I also built extensions, and I've embedded the Perl interpreter with no trouble at all. All I did was read and follow the instructions (I had done neither anywhere before). However, for some reason it wants to use dmake, which seems to be a make version not compatible with anything else this side of the sun. But using that to build Perl, then nmake for everything else as soon as it is built works just fine.

However, I have no idea what the take is on huge files in that build. So maybe you can't use it for that reason. And if Borland is fine for you, no reason to switch of course.