It took a long time for Flash game portals to get their shit together. There have been a few HTML5 game portals popping up but for an HTML5 version of FGL the portals have be successful.
I'd say seek out up and coming HTML5 portals and contacting them directly instead of waiting for an FGL for html5.
Still haven't found one that looks particularly promising. Wonder if it's worth founding one? Don't have the time though.
corp.playspan.com/ looks interesting. Took me a few minutes to find, and searching "spare change microtransactions" is mostly articles instead of the site, since playspan bought them.
I'm thinking the way to make html5 games is release with phonegap on iOS/Android, publish to a few web portals, and rake in microtransactions.