how hard would it be to buy one of these Sony DVD HDD Recorders from England, then have it fitted so it could be used in the Region 1 USA television market.
Take a look at this site. There, you will find a first class repository of knowledge on these machines. However, I suspect that the region hack (quite easy on these machines using One For All type universal remote) is the least of your problems.
I have a similar unit and shudder to think how difficult it would be to use without the broadcast EPG.That's the main problem; the need to program every record event manually is a rather scary thought. The second, but related, problem is based on the need for the PVR to control an external tuner, assuming that the internal tuner on a European unit is about as much use to you as a chocolate teapot.
These Sony recorders are capable of controlling external tuners via a small infrared transmitter on a length of wire plugged into the back. The recorder is capable of controlling a large number of tuners of different makes and types, but will you be able to find a compatible option? And once again, without a suitable EPG, will this be of any use?
I fear that the complications in trying to use a European PVR could outweigh the advantages. Rather than buying a rather closed system like the Sony, have you considered the options available using a dedicated Linux computer with the appropriate video hardware? See MythTV. A suitable EPG for North American use is available for a subscription of $20 per year.
Another alternative worth examining might be the Topfield PVR. While this is a unit designed for Euro use, it's far more open than Sony (there is a lot of third party software available) and a lot more expertise about what can and cannot be done.
Also, take a serious look at KnoppMyth. I suspect that this will be a far more satisfactory approach than attempting to kludge a closed European system for US use.
Good luck in your quest to buck the system; let us know how you get on.