If you're looking for used you can try this place - I've purchased several items from Davey:
DaveysJeeps.com Scroll down about a third of the way - the Libby skid plates are there.
You can also buy them new for your '07 - they aren't that expensive. All of them come with NutZerts to attach them to your Jeep. Check out this site:
WeRMopar.com. Do a search for accessories for your year, then go to the "Exterior" category and then click on Skid Plates. I've purchased a number of items from them too - fast turnaround.
FYI: There is a slight difference in the transmission skid between the '02-'04's and the '05s and later. Nothing that will impact the installation for you as there is more clearance provided on the trans skids for the earlier years than is needed on the later models.
Hope this helps...
Bob