There have been a couple of EVF solutions announced in the last few days which utilise a DSLR's HDMI output.
First up is the Z-Finder EVF
. There's a video of a nicely cosy fireside chat (my, but they're getting good at those) currently available from the site's front page
. Looks good but it will have to work hard to justify it's price, especially when one has to factor in the extra cost of a Z-finder if you don't already have one.
The second announcement is Redrock's microEVF
. There's a quick video promo available here
at Vimeo. I can't help thinking that this one will be the better value unless you don't need to buy a Z-finder for the Z-Finder EVF.
Neither is available yet so value for money is an open question.