This is the product the OP is interested in.



It has gotten good reviews and is affordably priced. http://velocouture.wordpress.com/200...ks-chainboard/
Sounds like you need the large size if you have a triple chainring. The two larger sizes (3 sizes are available) work with front and rear derailleurs. The only down side seems to be that installation can be tricky so you might want to have your LBS install it for you. OP, good luck; if you get it, please post a quick review.