I had written a fret calculator years ago. It's long gone,
AFAIK. I'd made it available to the world at large and a search for "fretcalc.exe" turns up a fair number of hits. I don't think any of them are the one I did all those years ago. With mine you could specify the number of frets/octave so you could get very exotic if you wanted to. Some of the ones I found with google print out, which, if they're at all accurate (questionable because you never know how well the printer is calibrated) is more usable.
Personally, I can't imagine wanting more than 24 frets. 21 is as much as I ever really need, but 24 will let you make a second inversion E major triad built off of the G string, so I'll tip my hat to 24. I don't really go that high up when I'm gigging anyway. Also, at some point your intonation is going to go totally into the crapper. Also at some point you're going to have to compromise between pickup location and the length of fretboard.
But follow your muse, I suppose.
http://www.winsite.com/bin/Info?26500000036994
KO