I really like the look of this, are you sure we can have custom colours and still have MOQ of 150 units?
Reading through the comments here, I'd go with the modern Windows logo, it's minimalistic and inoffensive. At a stretch I'd settle for Diamond logos, but please no blanks, it looks really strange to have a blank cap in between legended ones.
6u spacebars would be nice, for those of us wanting to build true MX-HHKBs or for use with modern winkeyed Cherry 1800 keyboards or the likes.