After buying a BusPirate v4 board, I’ve made a GUI that is compatible with the latest firmware.
In addition to a raw console mode with shortcut buttons for configuring the different modes, there’s also macro functionality and an oscilloscope for the ADC pin!
Source and version 1.0 available at code.google.com/p/jolly-roger
It’s built under Qt, and while this release is only compiled for Windows, there should be no problem in downloading the source and recompiling as long as you have the Qt SDK installed.
Feel free to edit source and add features! I built this as a handy tool for myself, but I think that other people might find it useful too!