Thanks to Fabrice Crohas, htcblueangel maintainer, who have been tackling at acx_cs driver since we were able to achieve first WiFi ping on h4000 and htcbluenagle with the help of devmem2, the PCMCIA support for ACX100 WiFi driver now works! It took quite some time to figure out what issue with PCMCIA was and make it work after first slavemem-connected device (hx4700) had first ping, but finally we're there - ACX is support on the great majority of devices which have it (though it is still has something in store, as couple of newest device have it connected via SDIO).
Working WiFi also means that all hardware on h4000 is supported now, and it has A- support status per HH.org classificaion, with the only missing feature being a native flash bootloader for Linux. Of course, not everything works great yet, or even fully tested, like flash write at all (but it is known to work for h6300 which has the same DiskOnChip and uses the same driver). ACX itself for one needs lot of work to make it support suspend/resume properly and PM in general.
But all those are just things to test/bugs to fix, and not white spots in hardware information/support. We're past age of "Linux will never be able to support that device completely" for another bunch of devices, and the future is bright! ;-)