Finally I got all types of PCMCIA PS2 units.
As the 10000 is well known to a certain extent I'll comment about the SCPH-18000 I just got.
It's similar to a US V2 PS2, has DVD driver built in (10k needs it to sit on the memory card) and PS1 exploit works with it (Doesn't work in a 10k due to kernel diferences. You can trigger the exploit but it will crash on the white screen)
It still require the HDD boot files (System Driver) to sit on the MC, contrary to what I thought it would be like. Homebrewn programs worked fine on it, including things like ulaunchelf and ExecFTPs including network adapter (which is a PCMCIA card) and HDD behaved properly with this one, just like it would on a USv1,v2,v3 or V4. In the 10k the homebrewn proggies which use network adapter related functions usually fail miserabily.
I tried HDLoader on this one, it did read the HDD fine, browse the games list but fails to boot them. Seems like the CDVDMAN patching is hardware dependant ... lol
These are PCMCIA units very first releses of ps2 that didn't have an expansion bay so you needed to connect the hd externally in that special enclosure