RE: four rotor toy
Today I watched two RCfliers fly new tiny one ounce helicopers with new DX8 radios - the copters had full collective pitch and wer fully aerobatic - I looked long and hard at the 1 inch by 2: circuit board which contained among other things a three axis gyro and a 2.4 rx plus an esc and two servos
the helis were absolutely glass smooth , steady -and lightning fast in response
The TX have only a small board in them too. Point being - the miniaturization of electronics is changing ALL the old rules and flying with a peizo pad is not as strange as it sounds -