Not quite, the low level macro facility provides hygiene as well (well, maybe not explicit renaming macros) with the ability to break hygiene when desired. These systems can be used to implement an unhygienic macro system (iirc, my defmacro about 7 lines, including the syntax case boilerplate).
R6RS standardised syntax-case, so any r6rs scheme already has it, but due to many things r6rs was a huge controversy and many implementations never started using it. Guile, chez, racket, Kawa, jscheme, larceny all support it. I expect syntax case in one form or another to make it into r7rs large, but you never know. Lots of cool things are making its way into r7rs large, including HAMT-based maps. There must of course be a vote, but that is just too good to not have :)
R6RS standardised syntax-case, so any r6rs scheme already has it, but due to many things r6rs was a huge controversy and many implementations never started using it. Guile, chez, racket, Kawa, jscheme, larceny all support it. I expect syntax case in one form or another to make it into r7rs large, but you never know. Lots of cool things are making its way into r7rs large, including HAMT-based maps. There must of course be a vote, but that is just too good to not have :)