If you would like to 'advertise' your desire for this plant on just All Things Plants, you can add it to your 'want' Plant List by clicking on 'Plant Database', typing in the plant you want, click on the correct plant, and then scroll all the way down and click on the dark blue button that says 'add to my list'. When you add it to your list, make sure you select 'want' (not 'have). This is a somewhat passive way of doing it since other members who have that cultivar won't receive a notification that you want it, so you would need to do a search and see who has it on their 'have' list, instead.
Some of our daylily enthusiasts on ATP like to go to the Lily Auction to try and find daylilies they want. It might be a little out of season right now (especially if you are in a northern state), but you can keep an eye on the lily auction website and even put it on your wishlist there (which will stay active for 90 days). Here is the website link: