Saw this over on the RCCA forums this morning. Looks like a great alternative to the TDR stuff.
EDIT: Actually, upon further looking, it appears like this may only work with a 36mm motor which makes it less than desireable. Boo!
Edit again: Make that 39mm, not 36mm
http://losi.com/Products/Default.aspx?ProdID=LOSB0017