It's open source, so people are welcome to. The reason for going back to 800x600 is to avoid having to use an even more expensive FPGA, and some related complexities. Also, in our experience from having used the earlier stages at 1920x1080 and 1920x1200, there simply isn't much need or use for this in an 8-bit computer in our view. But as I say, it is open-source, and folks are welcome to implement what they like, but our focus is getting something affordable out the door in a reasonable time frame, so we can't do everything that everyone would like straight away.
Paul.