Your DB skills are superb - Midday Sun looks like the ultimate match! Though it does not have formal rust testing itself, most of its ancestry does and almost all did very well for resistance! And, there is a nice picture from the hybridizer for Twenty Carrot at
http://www.daylilies.org/Dayli...
I'll go back to edit out the skyscrapers in my first post, to leave more room as people come to the thread to make additional suggestions!