I have to comment that you should have one version of GPD WIN with a 6" - 6.5" for ultimate windows gaming as many game titles have many small sized text fonts.
For example I am playing Star Trek Online and the sceen size while reading text is ok. 5.5" its too hard to read.
Also I have to comment that many umpc lovers would buy your product with a larger screen as a proffesional pocketable computer.
The ideal size would be an 6.8" screen like my Lenovo Phab plus that I am using as my main smartphone. Also the option to have a 4G model integraded (with BAND 20/7/3) would make MMORPG games played with joy on your device.
I like your products and I hope my opinion to help out to expand with a GPD version with a larger screen size.
Keep up the good work.