I just checked in the finishing touches on --prefix support for Module::Build. Module::Build 0.27_02 will have "perl Build.PL --prefix=..." to mirror "perl Makefile.PL PREFIX=...". More importantly, Module::Build's generated Makefile.PLs can finally emulate PREFIX.
IS EVERYBODY HAPPY NOW?!
EDIT:I forgot to mention that it was Rob Kinyon who took first stab at the --prefix patch and got me off my ass to finish it off. Everybody say "thank you, Rob".
This feature was auctioned off at OSCON 2004 and I wish I had the names of the folks who ponied up. Bill Odom probably has them, I'll see if I can get them from him.
EDIT: Bill came through with the names:
$90.00 - Tim Bunce
$20.00 - Curtis Poe
$10.00 - Unknown (I think it was someone from ActiveState)
Also Module::Build 0.27_XX fixes its --install_base locations. MakeMaker has an INSTALLBASE (or INSTALL_BASE, haven't decided) which matches what 0.27 does, not 0.26. So once Module::Build 0.28 is released I'll release a new version of MakeMaker that documents INSTALLBASE. Then, finally, you can install MakeMaker and Module::Build based modules using the same method. I strongly encourage the use of installbase over the fundamentally broken prefix.