K-Freddie that sounds like a really, really great idear.
I have been browsing the market, but have not seen any of these HMD's (Head Mounted Display) that meets the quality that I need contra the money that they cost

Most of the HMD's are very high priced and when I read reviews they are generally bad.
The common faults seem to be poor resolution and a limited field of view. And the fact that when playing games it becomes very easy to suffer from vertigo
I find it very interesting that you mention the fact, that the displays will be upgradable as newer versions with higher resolution become available. This is also something that is not on the market yet and will be a great way to prolong the life of the HMD, which othervise could prove to be an expensive adventure.
The resolution that you mention in your post is that the true resolution or do you have to split it up into RGB? So the true resolution is more like 266x200?
And will the unit show true 3D or just two identical pictures
I am under the impression that it will be hard to get good displays for a HMD because of the supply and demand of this item. The demand for small displays are very high as they are also used in mobil phones, which has a very, very big market compared to say the market of HMD's. Do you have a good and reliable supplyer?