So I couldn't help but notice that a lot of the hidden base designs in minecraft are cliche and obvious, the two I am about to show you would never be found legitimately unless someone saw your name through the ground or followed you.
I don't know what the official name for my first switch would be as it's kinda like a BUD switch, but not really. All I know is that it works pretty well! The concept is described in the video, but it is not a BUD switch in that it only reacts to certain block types. The second works off of my pressure plate 'bug' thing I posted.
The first one that is, the items go through the pressure plate and hook up to a T flip flop as shown.
I hope you like the video or can find it useful.