Due follow-up on this topic: I have been tracking offers for the mentioned above HP/Lenovo models for few days, then bumped across a second-hand Thinkpad x240 in B+ conditions (just few insignificant scratches on the surface), equipped with a backlit keyboard of the desired layout, a 256GB SSD, bluetooth...for 200€; it seemed like a good deal, so decided to opt for that one, it was delivered few days ago.
Installed NetBSD on a CGD encrypted FFSv2 root (no LVM). Built a monolithic minimal (11MB) kernel, with enhanced hardening (again full KASRL including kernel image, PaX Segvguard, Veriexec), running smooth.
My feedback: finally able to test NetBSD 9.0 on a well-supported machine with good-enough specs, I must say I was very positively impressed by the overall performance and stability of this new release, amazing.
What works: Intel graphics (had to switch to uxa acceleration method to prevent flickering), XHCI, X multimedia keys (at sofware level, with xbindkeys), backlight, trackpoint, wireless (in 11g mode), webcam (tested with cheese), bluetooth (tested with a pair of wireless headphones).
Mostly working: X240's touchpad doesn't have physical buttons and that's a real shame. With the default pms(4) settings it was almost unusable, but fortunately, after playing with different hw.synaptics settings, now it feels really smooth; I have 2 finger tapping, proper middle and right click emulation, proper acceleration and edge scrolling. Tempted to test current on a external hard drive to check whether 2 finger scrolling works, given @nia's recent commits
What doesn't work: suspending/resuming; when trying to wake up from S3 kernel panics (even on GENERIC); a quick trace revealed that it had been the iwm(4) driver to cause it. I'll investigate this further.