I can't find the link right now, but there is an all electronic (no
spinning gyro) attitude instrument available for experimental aircraft
in the $1200 range. Essentially replaces an AI or TC. Has a yaw
indicator and lots of other functionality. It is square but fits in a
round hole (no one makes round led screeens). Non - TSO of course. Not
sure of the exact technology behind it, but it works and is not any
more expensive than a traditional all electric AI.