Hi Scrump
What you're after is a battery-powered pre-amp. I've seen them but never used one myself. For the "ream out the end-pin socket so it will take a jack socket brigade" I got a great gadget when I lived in the US. It had a jack plug which plugged into the socket, it was slightly larger than a matchbox and had Hi, Lo and Vol sliders. Sadly, it got stolen and I can't remember the make.
Shadow Elektroakustik do almost the same thing on-line in a cable – try www.shadow-electronics.com

Eddie