Well, the shop always sold stitch guides but they have a new online store and have a section called "Stitch Guides." Hurrah! This is a new venture so for now only two guides (by Lani and Robin King) are listed. I imagine this will grow as the online store itself grows.
Remember, BeStitched also has a section called "Pax" which are kits: canvases, stitch guides and threads. If you need the entire package (usually from their classes) this is the place to look. But buyer beware--I am told that classes usually include access to videos illustrating stitches and techniques and these are not part of their kits. It also is wide to read the descriptions carefully as some kits seem to have more than others.
UPDATE: The shop also has video stitch guides for their retreat projects. These are short and demonstrate sections of the canvas to help those working the project.
UPDATE #2: BeStitched has added PDF download stitch guides to their Needlepoint Fix Marketplace. Right now guides are available for canvases from dede Odgen, Ewe and Eye, Kelly Clark, Maggie, Melissa Shirley, Tapestry Fair and Zecca.