I want to put roll edging in my yard to create clean breaks between the grassy areas and the planting beds. My yard does not have a uniform slope however. It has multiple grade breaks in all directions. Is there a roll edging product that can be flexed in the skinny direction (up-down?), as well as being flexible in the wide dimension (back and forth).
I cannot recommend strongly enough that you NOT use roll edging. You will never be able to get a good look with it because it "memorizes" its original rolled up shape and kinks badly (even on curves), you can never get straight lines (due to kinking), it has horrible (or non-existent) stakes, and many brands are at most 3" thick when they should be at least 4" thick to prevent grass incursion into your planting beds. Stick edging is also FAR easier to work with than roll edging.
Professional landscapers use stick edging, not rolled.
If you go to a garden center instead of a box store, you can buy 20' long sticks of plastic edging that come with four STEEL stakes and a (usually pretty wimpy) connector. The connector works fine unless you're trying to create 10' circumference circles, which won't be a concern with your project. Box stores do not usually carry this product.
Also - never just butt two pieces of edging up against each other to connect them (whether rolled or stick). There is a simple trick that requires a little work but ensures that the edging will never separate or frost heave (send me a comment if you want more details).
In answer to your question though - no, I've never seen any edging (plastic or metal) that flexes vertically (would love to be proven wrong here). The only way you can account for changes in terrain like you describe is with bricks, stone, or bulletnose pavers. If you go with bulletnose pavers, do not get any less than 4" thick - I've seen some as poor as 2" (but they were only a buck! Woo Hoo! More weeds!).