I e-mailed Nick at N-Gear "jump stop" and asked him to send me one of his...
http://www.gvtc.com/~ngear/
Apparently he sends it to you and lets you try it before you pay... not bad and it' only $12.
My thoughts are that I have a bit of a mismatched drive train... 9spd 105 front and rear derailleur, kmc 10spd chain, and rival compact.
My guess is that all of this paired with cross chaining before shifting, causes the chain to drop. I have worked on the bike on the stand, and the small ring has a hard time catching the chain when in the big 2/3 cogs in the back. As i can see the problem is when the chain tries to angle off the big ring, the angle is to great and the chain over shoots the small ring, After the FD... if that makes sense. the FD is also aligned properly with the crankset.
PS. I have the lower limit on screw set so that the chain just clears the inner plate of the FD when in the Big back/ Small front combo.
I think I already said all this but that's whats up... I will tinker with it a little more today, and when I get the jump stop I will let you all know what i think of it.