I was inspired to do this after taking a good look at the JCM800 emulation on the main site.
I essentially changed the "preamp" section of that design to JTM45 specs, added a presence control (which I hope works), put in Fat and Bright Switches, and borrowed the speaker emulating filters at the end from Runoffgroove. The schematic I used to guide me is from http://raw-sewage.net/images/jtm45-readable.jpg
Here's the vero layout. Currently unverified, but those of you who are ambitious can feel free to beat me to it. I have high hopes for this one, if it sounds the way I want it, it's getting boxed together with a rangemaster build and replacing my Plexi-drive build on my board.