I switched back to makeslapt as default, so if you want to use requiredbuilder and makepkg just set RB=yes before running pkgmk
Nice. I like your added "RB=yes" switch so users can use what they like.
I took our little "project" a bit further. Based off of your latest pkgmk I made these changes.
1) Prettied up the "Add your name" prompt. Also relocated it so user won't have to enter their name to view --help.
2) Requiredbuilder/makepkg can be invoked by using -rb or --requiredbuilder or "RB=yes"
3) User can make packages for 5.8, 5.9, or 6.0 by using -vl58, --vl58, -vl59, --vl59, -vl60, --vl60. But vl59 is still the default if nothing is specified.
4) Updated --help So our new settings aren't hidden/secret.
also a lil bugfix in my earlier code. I did modify your "vlver" switch. I needed one as well and thought it better to modify yours rather then add one more.
Here's the complete (updated) pkgmk file:http://pastebin.com/f336eebd4