Check Mark, Inc. is another company I have completed several assignments for with all very good experiences.  They do list some available shops on their site and have some good accounts.  Another plus for Check Mark is often their pay seems better than industry average.  I have provided  a link below to Check Mark, here's how to navigate their site:

They have an into  video that  can be skipped.

Click on "Shoppers"

Click on Apply for Mystery Shopping

Fill out Application

After recieving approval,  login, and click on "Sign up for Shops."  Searching on Check Mark can be done either by state or radius of a zip code which is great for secret shopping on the road because profiled zip codes don't need to be changed.    They also have a section to view "upcoming shops."

Check Mark, Inc.

Blog Sponsored by MyPoints...earn points for reading emails and cash in for great gift cards.