Melissa Prince's canvases are becoming more popular as they become better known and more guides are being written for them. Right now World in Stitches is having a trunk show and they've posted photos of canvases with their guides. The photos aren't great but you can see at a glance which canvases have guides.
Here are earlier articles on the CH Stitch Guides Blog about available guides for Melissa Prince canvases:
Hopefully the guide you want for the canvas you admire is listed above!
UPDATE: Here's Melissa's Chickadee, guide by Patricia Sone.