thanks for a helpful response
I'm probably going to drop by my local DIY electrician to see what he suggests...
thanks for all the less detailed responses also, however electrical DIY solutions are easier to make more elegantly than mechanical DIY solutions in my experience so I'm not too worried as long as the necessary precautions are taken
There are off-the-peg DC adaptors which might be adequate if you knew precisely what voltage and max current you needed... one problem is that it would not be a constant load (current requirement).
All electronic kit needs DC, so you would be better off at you local electronic store, e.g. Maplin, or on the internet.
A simple solution would be a battery of the right voltage and max current in conjunction with an auto charge rate battery charger, as the battery would, to a large extent, protect the camera from the power... you would need a fuse or circuit breaker on the ac and dc circuits.
The DC voltage might not be critical, as the camera is designed to run off a battery, which would not have a constant voltage... but some batteries (e.g. the rectangular 9v batteries) are designed to produce nearly constant voltage... unlike a car battery, which produces an output of between 6 and 15 volts, and (due to low internal resistance) can produce dangerously high currents likely to cause fires.
If you had an unserviceable camera battery you could connect to that.
... but it will invalidate the warranty.
You could simply connect a computer to it and power it through firewire.
It should not be very difficult, but don't blame me, I advise you not to try.
If you are using you camera enough to make it worth thinking about an ac/dc adaptor, your time would be better spent using the camera.
I am an agricultural, mechanical, electronic and software engineer, and I am contemplating using my skills for robotic remote control of cameras, and shift/stitch and computer programmable focus for focus merge in macro.
