AZ in Colorado Springs
Kinko's can print pretty large. As for copying, I've used them for
1) my son wanted a practice rifle for the drill team. He found a photo of one, and I had them enlarge it to the length we needed. Then used it as a pattern to cut it out of dimensional lumber, and
2) I made a doll cradle from scratch, making it up as I went along. When complete I didn't feel like drawing up a plan, so I disassembled the cradle and took the parts to Kinko's and got photo copies of each part. Much easier. They charge by the square foot.

The "two nails and string" method will make an ellipse -- which may or may not be the "oval" you have in mind.