On the trip back to Berlin (from netconf in Tokyo) I had the first real-world test case for my new Panasonic R5 laptop. This really is the best laptop I ever had, I'm very happy with it. The advertisements of 10..11h battery life time don't seem to be an overstatement. I'm not flying for more than 10 hours, but given the power readings that ACPI gives me, 11 hours should be very much possible, given the total power consumption of 4.3W while doing text file editing, such as writing program code or this blog entry.
Doing a kernel compile brings the total power consumption up to something like 8.9W, still pretty impressive (and should give about 6.5hours given the battery capacity of 57Wh).
On the driver/hardware support side: I got display backlight control to work with the out-of-tree pcc_acpi module, and ipw3945 also worked straight ahead. Now I basically only need to find some useful thing to do with the TPM that I unvoluntarily got with this device. Has anyone figured out a way to use it for dm_crypt key storage or something like it? That would be neat. And yes, I know, if the device breaks, my data is gone. But that's what backups, version management, IMAP servers and the like are for.