Just read
this article on the VM website.
I know Sony are planning a similar service on PS3, and it is something I generally would be in favour of. I belong to Amazon's DVD/Blu-ray rental scheme, and if there's one thing I dislike, it's putting some of their frankly filthy discs into my DVD player or PS3 - so a download would be ideal.
However, if I'm honest, I don't think the world is ready for downloadable movie rentals, whether they be standard or high definition. The UK certainly isn't. When you think of the multi-gigabyte size of a hi-def film, and then take into account (a) the relatively low general speed of UK broadband and (b) the relatively low bandwidth caps that most ISP's impose, you'd have to be pretty daft to use your internet connection for HD movie downloads. And it's a situation I don't see changing for quite some time, particularly here in the UK, and maybe in the rest of Europe too.
Interested in hearing the views of others on this.