Sorry Ben,
I think Denon/Hayden are feeding you a line here...
If there WAS a multiregion firmware available for download (for the 3800) anywhere on the net I would have heard and tried it by now. There isn't, I can assure you (believe me I've looked extremely hard).
The only way there is out there at the moment for screwing up your player is to try and upgrade it with a copy of an american firmware update disk. The no. of people willing to try this is minute.
I have only seen two people who have owned up to this, whose machines are now working perfectly with the firmware downloaded from Mr. Merrick (thanks mate).
A similar story emerged for the 2800 ('it disables players features') which was sufficient to put many people off doing the firmware upgrade themselves (me included I might add - I paid my dealer the £30 to put the CD in the tray and initialise the machine..not good value for money!). It also provided a wonderful scapegoat for the problems many users then had with their 2800's.
My personal theory is that Denon are having some problems translating the firmware fix for the chroma bug to PAL machines and this is what has delayed any new firmware (and subsequent hacked firmware).
I think you'll find that the same persn telling you these storys is the same one who offers you a disk 'anonymously' very soon! Ask a few of your customers for A-1s too..they should be able to put you straight.
Regards,
Ian Guinan