I think plastic canvas is great! I've mainly made kleenex boxes, coasters, project bags, ornaments, houses, etc. One of my best finds of an already-created plastic canvas creation was a wine tote made by a senior citizen in a small town in northern Minnesota for their senior citizen craft show. It was amazing.
I don't know if Mary Maxim or Herrschner's have patterns, but they do always have kits that are cute and reasonably priced. I also like a prior poster's suggestion of ebay - for both patterns and supplies.