I cannot think of any websites that might have what you are looking for off of the top of my head, but if I think of any I'll post them.
I personally make my templates out of MDF or hardboard, but any solid, void free sheet good will do. I like MDF because it machines easily, with no grain or voids to deal with, it is naturally slippery for the router to move across, and it is CHEAP.
Draw out your pattern, put the correct offset of your template guide/bit combination, and rough cut on your bandsaw or scrollsaw. Sand to the line and you are good to go. If you make a mistake, mix up a little bondo auto body filler and repair your template, then sand again. You'll be amazed at how fast you can work MDF into a quality template. If it is something you will use a whole lot, you can then copy your template into Acrylic, phenolic, HPDE, etc. Just make sure you label each one so you know what they are for!
You can also cut the curves for your template using your router instead of your bandsaw, simply make a simple router compass. I use a piece of 1/2 x 6 poplar, about 2 feet long. It has a hole in one end to accomodate a 1 inch template guide bushing. I simple chuck up the bushing in the router, slip the router into the compass, measure out the radius I need (making sure I go to the correct side of the bit) and then drill a hole for the pivot pin. No need to swap baseplates to use this style of compass.
After your first couple of tries, you'll be making templates faster and cheaper than you can buy them.
If you are doing a lot of corners with your corner template, make sure that once you get it set up on the first corner you screw some indexing blocks to the bottom. This way, you'll have no set up work to do as you go from corner to corner.
Make sure you check out Template Tom's posting under the "portable routing" section of the forum. He has a great 5 page write up on template use and hints.
Good luck, and make sure you post some pictures of your finished work!
All the best,
