To answer my own question about re-encoding, it looks like the HD-DVD spec does allow for MPEG2 which I did not think it did. So Danny is right, it will be a case by case basis to determine the quality of these releases.
Regarding HD DVD region coding, or rather the absence of it at the present:
There is no region code embedded in the current software, or region-code checking in the players, because no region coding system was developed at launch. You may also find it interesting that a Toshiba representative who was interviewed for an AV Forums podcast is on record saying first-generation European models will not become region-encoded via firmware upgrades, ever. I don't see why it would be different for first-generation American players; i.e. anyone who bought a region-free player should be OK in the future as well.
Nice, Les Chevaliers du Ciel is pure Military Plane Joyness, i tought those were the best plane camera work since Top Gun (the real thing, no stupid CG Crap), the story is Mega Cheesy, but who care it's all about planes and sound!
Can someone please confirm that these import HD-DVDs are 1080/60? I've done some research on Euro HD, and I get the impression that Euro broadcast HD can be done at 1080/50, which would mean the same 4% speedup and audio pitch distortion as legacy PAL. However, I've also read the spec for HD-DVD only allows for 1080/60, but cannot confirm this.
BTW, HD DVD discs containing high definition content at a field rate of 50Hz or a frame rate of 25Hz can not be played on current European HD DVD player without a firmware update. Firmware update is expected in the future.
Broadcast HDTV in Europe has absolutely no effect on HD DVD or Blu-ray releases. HD displays are capable of multi-syncing and will support playback of 1080p at 24fps (which is how HD DVDs are encoded) natively.
European TV-sets have supported NTSC (and 60fps) for a long time already, which is rather easy (technically) if your native frame refresh is 50fps.
This goes even further than I thought. My "old" TV set (approx. 7 years), when I was testing the Toshiba HD-A1, appeared to have no problems at all with a setting of 480p output of the player, which is surprising.
What remains to be seen is if these HD DVDs from "independent" companies match the PQ/AQ of the North American Blu-Ray editions. I'm guessing they don't necessarily use the same masters or encodes á la Warner or Paramount's dual releases.
Additionaly, some of these foreign releases seem to go out of print quite rapidly. The Japan-only Equilibrium HD DVD appears to be OOP already.