Hi
the main point of that RSS template is to manually create RSS feeds via an easy to use interface rather than writing code etc. Although the LO plays via the flash engine really the point is to share the RSS link created for use in an RSS reader or feed consumer etc So although the LO plays via the Flash engine I don't think that project template is used much in that way, it's simply used to generate the xml, copy the feed link and share that somewhere and for that to happen you don't really need a HTML 5 player especially as you currently need Flash to create the feed in the first place. That said once the work on the new editor is finished perhaps it would be useful to build a HTML 5 player view of the RSS template and I've always thought it would be good to extend that template anyway to allow media upload and for instance to create podcast feeds in the same way.
In short no HTML 5 playback of the RSS template doesn't currently exists but there might be justification to look at this in future and to extend the functionality at the same time.
HTH
Ron