First, it might be helpful to know that daylilies are not bulbs....and despite their common name, they are not even true lilies. They are fleshy rooted perennials.

The classic rebloomers are 'Stella D'Oro' and 'Happy Returns', together with their recent cousins, 'Black-Eyed Stella' and 'Rosy Returns'. All of these tend to be rather compact plants for daylilies and should stay well under your 30" height requirement.

There are also a number of newer intros that have reblooming features and these tend to offer a wider selection of color choices but you may need to seek out a daylily specialty nursery (many online - just Google) to see the full range. And with new daylily intros, prices can range from very modest to ridiculous.

You might want to post this query on the Daylily forum as well -- you'll probably get far more responses and more detailed ones at that.

I now have a wonderful daylily that blooms up to frost and is also one of the first to bloom in the spring. Unfortunately I don't know its name. All my daylilies I have received from friends gardens as gifts. I am propagating this plant as fast as I can so I will have a lot more bloom, even if less variety. Just so you know there are some really good blooming daylilies available today. Al