I don't personally want to put a lot of effort into the gratuitously changed, messed up, sloppily modified but at least it builds and largely works even on a 64 bit machine 0.7, but this is further pushing the bounds of a working implementation as required for the SRFI process.  Too much?

That is absolutely a SRFI Editor question, not for me.  This is the first time I've written an inherently non-portable SRFI, and I don't know where Arthur will set the boundaries.