The SerialUSB improvements that were merged into the master libmaple branch have been incorporated into the IDE. Snapshots are available (no 64-bit Linux yet; I hadn't gotten around to making a 64 bit VM to compile dfu-util in, but will resolve that issue soon):
Linux (32-bit):
http://static.leaflabs.com/pub/leaflabs/maple-ide/snapshots/maple-ide-snapshot-2011-02-13-%5Bgit-1780be0264%5D-linux32.tgz
There've been some issues lately with the built-in serial monitor; if you get bad behavior, try using something like PuTTY, HyperTerminal, screen, or minicom. Working on fixing this as well.
The next snapshot release will include a 64 bit Linux version, as well as basic DMA support and miscellaneous other improvements and bugfixes to libmaple.
