I mean for Google Sitemaps. Would it be possible to use your HTML sitemap and have Google Sitemaps read it? Obviously it won't work yet, but is that a possible update for the future?
Why not just generate both kinds of sitemaps? Anyways, Google already crawls, on its own, HTML pages... So if you have a HTML sitemap... Google will also to some degree crawl that (in all likelyhood)