Yeah - the Xtrak is popular. Triple X had X Trak make them some custom front a rear sets, at $50. I ordered a set last year - pretty hard EVA - I didn't particuarly care for it, but it's cheap. Also, Triple X had it to me in less than 3 days Florida to California! http://www.triplexsurfandskim.com/Accessories_amp_Apparel/Wakesurfer_Traction_Kits_c24/
LakeWakes makes up a set using the Long bow tail and the Xray front. Also $50 http://www.lakewakes.com/xtrak-traction/xray-kit/prod_26.html
Snapspeed carries the "stripper" front pad for $24, PITA to apply if you break the strips off, but I like the feel of it...a good option of you find a kick that you like but need a front. http://www.snapspeed.com/XTRAK-STRIPPER-SURFBOARD-TRACTION-PAD-p/xttstp.htm
Wakeoutlaws carries some traction, I think mostly the long bow full set - pricey and probably more traction than you need. I see that their site is down for 2010 updates.
Surf Source carries Huladek - clear nonskid surface - @ $20, not as good as the EVA traction listed above, but is pretty good for most folks. http://surfsource.net/Sticky%20Bumps/stickytraction.htm
I can't find it now, but there is a hobby shop that sells sheets of 3M adhesive backed EVA - 1/16" thick that works ok also. You might try a google search for EVA and 3M
Hope that helps.