I built a couple cloverleaf antennas for my 1.28ghz video transmitter. Instructions can be found at RCExplorer and on RC Groups. (I like the instructions at RCExplorer better, they were less confusing)
So far I have only had one flight using my cloverleaf antenna (my Fall colors 1 video), but it preformed quite nice!
It looks a little ghetto with the black tape, I will figure out a better way to mount soon. :-]