John,
> Basically... I'd really like to discontinue ALL of the other options..
Just do it, it will save you a mountain of grief and reduce the number of complaints by the illiterate. I made this decision early with ML64 and provide 2 options, a stack frame that write the appropriate registers to the shadow space and the rest of the arguments to the correct stack addresses and for the brave or those who actually know what they are doing, no stack frame at all.
Anything much in between is a complicate mess full of potential mistakes, un-necessary clutter and a documentation nightmare. Free of the crappy end it allows you to concentrate on the things that make the assembler better.