Hi,
I tried Pd with the latest version of Raspbian on my RPi again tonight, and I managed to get no (actually very few) drop outs with a buffer of 6 ms, using my USB E-MU 0404 soundcard for input and output at 44,1KHz. The patch I used was a very simple feedback delay and I tried it with my guitar. I think this is insane. This makes me very happy.
Cheers,
Pierre.