I've used Shutterfly to order canvas prints. It's still ink and not oil paints, but it is on canvas. The result isn't glossy like a photo print, but it also doesn't show brushstrokes like a real oil painting, although I guess you would still see some if you sent a picture of an oil painting. They love sending out coupons that make it reasonably affordable. The canvas comes mounted on an internal wooden frame.

You'll probably get copyright questions if you submit an professional artwork, but if you can show it is in the public domain they might do it. I've never tried.