Experimental Musical Instruments is an online resource for people who want to make unusual musical instruments. They have how-tos on instrument making, as well as books and CDs featuring the work of experimental instrument makers. Also they have back issues of the Experimental Musical Instruments quarterly journal.
They sell supplies for the experimental instrument builder: pickups, tuning keys, zither pins, fretwire, and other specialized hardware for makers. They sell piezo transducers, and piezo film if you want to make your own.