Ladino and durana are really good choices, as N2TRKYS mentioned, but both are really slow to establish, so i would mix in some patriot clover with it. I also plant cereal rye with mine as a cover crop at about 75lbs/acre. Durana runs about $5/lb. To have and keep a perrenial clover plot, your soil needs to be able to hold moisture and be partially shade during the hottest parts of the day during late summer, or it will be toast. Rainfall is sketchy at best that time of the year. Make sure before you spend that type of money, that its a good place for a perrenial clover plot.