The D&D 4e character builder works OK for the official classes, but doesn't seem to have much support for anything custom. Are there good tools for managing characters with custom (homebrew) classes?
There is a 3rd party app, cbloader, that can be used to extend and create new content for the offline version of the character builder (which you would need to find a copy of).
You should be able to implement a custom class in that, though you will need to know how to edit XML files.
RP Tools' Character Tool allows for a way to update the databases that contain character classes, and then build a character with that class. The problems with that are you have to do it manually as the editor is in development. Also, only a small portion of the existing D&D classes are entered into the tool. And lastly, it doesn't enforce any of the rules (only 1 feat/every other level etc.).
4eTurnTracker lets you program customized powers for both characters and monsters. It extends full functionality to customized classes so long as you take the time to "program" everything in. It's also easy to mix and match stuff from other characters, since 4ETT lets you import and transfer anything in plain text as well as formatted text.
Mind you, 4ETT isn't designed for printing out character sheets, per se, so much as keep track of everything else during play. Still, since you can just click on your powers and then click on targets and have all the dice rolled and effects applied and tracked, having custom classes in there is the best of both worlds :)