For anyone interested in low-water gardening

I'm looking for a garden plant database that is searchable by the qualities of the plants as well as their names, cultivars, etc. You know, like an advanced search on a fanfic archive, only instead of fandom, pairing, and genre, it would have zone, light requirements and water requirements.

Dave's Garden has huge databases for plants, bugs and birds, among other things, but the search function is really limited. (N.B.: Dave's Garden is about the best, most overwhelming garden website there is. Registration is free, and extra stuff is available by signing up to a paid option.)

Has anyone ever seen any kind of database like this on the web?

I've been doing a lot of Googling in the hunt for xeriscape information specific to my area. Eartheasy has a nice list of plants, shrubs and trees that are supposed to require less water than the usual.

But, lazy woman that I am, I want a list specific to my own area--zone 6b. I've email my county ag extension office and I hope to hear from them tomorrow or the next day. If I find any websites that are more detailed, I'll post them here.