Most compact way to connect pressure plate and piston
Solution 1:
If you have sticky pistons, this type of wiring is pretty compact:
Solution 2:
Just run the redstone up. Very resource friendly (no repeaters) and tileable. Though will cause a little bit more lag.
Solution 3:
Old question, but nevertheless: You can do it a bit more compact. You just need one repeater and one redstone.
