Form factor of a late 90s / early 2000s (1.5-2" thick, 15" screen size or so) laptop. None of this thin-and-light nonsense.
Sunlight readable display capable of being used in reflective (backlight off) mode for reduced power
Optional cellular modem module
Two (or more) externally accessible, hot-swappable 100Wh batteries with power ORing. If you're going on a plane you can take some of the batteries out to make the FAA happy. But if I'm on the road I want the option to have several batteries and swap them without needing to be plugged in or shut down. The goal is to support multiple days of off-grid usage with no charging access.
1000baseT and 10G SFP+ Ethernet ports
Lots of USB A and C ports. 5-10, at least, spread across several roots for improved bandwidth
Modular, repairable, upgradeable design so I can e.g. swap out the CPU board when it becomes obsolete but keep all of the peripherals and chassis
