I have an old yamaha se203 that I'm trying do make really unique. I was wondering if i could somehow Put an acoustic pickup in as apposed to one of the stock electrics. any ideas?
alright, this is the style bridge i used it on:

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basically, you buy brass piezo discs on ebay (i got 10 for 5 bucks), i ordered 15mm, but i would maybe get a tiny bit bigger.
the brass part of the disc is your ground. your bridge should be grounded, so setting the disc on will ground it. then you just need to run small wire to the piezo film on top. i made a pade of 3 discs, so 2 saddles sit on one disc at least partially. i stripped the wire, and pulled half the strands one way and half the other way to the wire is kind of split in half, and ran it to the film both directions. the black squares are electrical tape so the strands dont touch the copper.

now, i have a black bridge, so i used electrical tape over the top of the wires and everything so its all unseen. youll have to find something to cover them with so the saddles arent directly on the film as it will tear easily.
the bridge has a middle screw hole in the back and one in each corner. i left out the middle one, and ran the wire through that and into the body.

then you will have to make, or pay someone (hint hint.. jk) to make this buffer, to get the signal to a more normal level for your amp. it will need a square battery.

its really very easy. ive never made a circuit board kind of thing, but i made that easily. that actually cost about 20 bucks, but thats because the parts came in packs of 20 when i needed only one...