44 pin cables can be found here: http://www.cablesonline.net/44pinlapinri.html
Signal levels should also be fine, as they are specced at TTL levels (2.4v for 1 and 0.something for 0), and as far as I can tell the CF slot should be 5v tolerant.
But that is a good point, this is all theory at the moment.
I think you're right. I remembered some people using a powered external enclosure with a PCCard adapter (on a Pocket PC) not long after I posted.
That's brilliant, thanks. Unfortunately, they want $26 to ship a $6 item to the UK. There must be a UK-based supplier somewhere!