I recently created a nifty little tool for generating custom fretboard charts than I'm happy to be able to share on the FATpick website. You can use it to create a fretboard diagram for any tuning, any number of strings and any number of frets, like this one mapping the notes on the neck of a 5-string bass guitar tuned to B E A D G out to 26 frets:
The tool was originally created to generate illustrations for our dictionary of guitar tunings but I thought it would be neat to set up a simple form that lets you experiment with it more interactively, and so I did.
Like the pages in the tuning dictionary, the fretboard generator is to be printed as well as viewed online. Just print the page directly from your browser (File > Print) and (through the magic of CSS media queries) all of the web page cruft like the header and footer are stripped away and you're left with a simple and colorful fretboard chart you can pin to the wall of your practice space for easy reference.