Nice! Lots of Triplecross fans here, including myself. You probably need 110mm BCD chainrings for the larger two if you have a Exage triple crank, like mine had stock. I like the Stronglight chainrings that came on my Stronglight Impact compact crankset from Ribble, but there are lots of others out there.

To put an additional chainring on the front of the 714 you would probably need a new crank, bottom bracket, and likely a long-cage RD and compatible FD, which could get expensive. Another option may be a compact crankset and a longer range cassette in the back, which also might require a long cage RD.