My SanDisk contact sent me a Sansa "Dev Board" with a JTAG cable attached that arrived on August 7th 2006. I took a few shots of it, see below.

I have not tested JTAGging with it yet. The pinout seems to be this pinout suitable for this cable. We have a Macraigor Wiggler ready.

The board reports itself as a "Sansa e260R", 4021 MB. Boots up with a 'Rhapsody' logo (when I insert the USB cable, it has no battery) and its 'sda2' partition is 6.5MB compressed.