The problem with Brother printers has been solved. Their installers use the Debian post-install script to create the key files (the filter and the PPD) and want to use paths like /usr/lib/cups. So it's just a matter of symlinking the correct paths, running the installer and extracting the driver files into a TCE. After that, the symlinks are not needed. Unfortunately, each Brother model needs its own TCE.
The Brother drivers do not use foomatic-rip. My sense of foomatic-rip is that it's been made largely obsolete by newer packages like Gutenprint and HPLIP. However, you still need it to use the built-in Ghostscript drivers. FWIW, there is a new compiled version of foomatic-rip that eliminates the need for Perl.
I've had a look at CUPS 1.4 - lots of changes! I couldn't get it to compile so the Printer Maintenance option would show.