With the spiffchorder you are free to put any kind of key switches on any kind of surface or material and make it a chorder. Plastic, leather and cloth have been successfully used as the base materiel and a variety of items ranging from conventional keyboard switches to conductive fibers have been used for the “buttons”.
If your palm or hand held pim can take a usb keyboard, then build a cradle for it out of plastic or leather that has a built in chorder. Now you can enter notes or other text with the hand that is holding the pim! Your other hand is free or you can use it with the stylus.
Office supply stores still have plastic sholder rests. These often fit well in the hand and can make a nice base to build a chorder on top of. I did a version of this in the pre-spiffchorder days. Its construction is documented at http://www.cs.vassar.edu/~priestdo/chordhack/phonerest/. It is leather that is then brushed with hot bee’s wax.
I have started a separate page for 3D printer files for chorders. It’s near by though, right on this wiki at 3D Printer Files for Chorders.