> and the lack of visual and system-level customization options takes a lot of the joy out of system setup, management, and exploration

Exactly this. A good part of the joy I get in seeking out an awesome ultra-portable (and in doing so, experimenting with my mobile workflow) is the high customization I get from Linux machines. Sadly the two best portable contenders (ChromeOS and Windows) in terms of feasibility, don't meet this.