Reply to XY pad on mixers?

Has this been done before?

Would be nice to see Pioneer/A&H come up with a decent XY pad on common club mixers ( e.g DJM900) to control any 2 assignable parameters, which can be set to release when you take your finger off.

I believe most of you will know what I mean.. Sometimes it feels like you need another pair of hands to control multiple knobs/faders, especially when building to a drop.

I say this because I'll often use fx such as echo/filter as a track is in a breakdown and moving towards a drop.. and at the same time as the track drops I need to hit play on the next track.. BUT you need to turn 2 knobs back down (e.g echo & filter)... Shit I've run out of hands...