When Archos initially announced the 605 WiFi and TV+ in June of 2007, they clearly were talking about a plugin to support 720p content:

Archos has been saying HD was not urgent but would come when video-on-demand in HD would be available.

I think that the key reason for the delay of the release of HD support could be the requirement for DRM to work for HD. And the solution to 720p HD video DRM for Archos might be in the recently announced partnership with Widevine: http://www.webwire.com/ViewPressRel.asp?aId=60960

Which basically allows Archos to sell HD content in the Archos Content Portal encoded in other formats then WMV. The basic thing that could have delayed the release of the 720p plugin could be that WMV does not work on the current generation Texas Instruments DaVinci chip, but that only less processor intensive 720p Mpeg4 Simple Profile such as Mpeg4 DivX or Mpeg4 XviD would work. So now, hopefully, with Webvine as a DRM technology partner, now the DRM for HD video content could be using any codecs including Mpeg4 Simple Profile.

The simple fact is sure a few people have DivX 720p content (like I have published 1000 DivX 720p videos on my video-blog the past 3 years), but most people do not have DivX 720p content. And content providers, the big movie majors will not allow Archos for one second to put unprotected DivX 720p movies on their content portal. But if they get a technology like Webvine to somehow put DRM on DivX or other types of Mpeg4 Simple Profile 720p, then that could be the solution that we have been waiting for.

I don’t know if the Dish Networks type 720p or 1080i Mpeg2 recorded content will work. Hopefully it will work, and that would be protected by Dishes own DRM system which is already implemented for non-HD content.

Adding HD support and HD content to the Gen5 could be absolutely huge. This could be a move from Archos to directly compete with Blu-ray and become a product of choice for customers who have HDTVs and HD projectors.