I debated with myself (and others) quite a bit about keeping or losing the original Paia pins. On one hand its cool to preserve the integrity and original aesthetic of the synth (not to mention the time removing all the little buggers). On the other hand, they're the same size as banana plugs, they do look somewhat similar, and banana plugs are more useful to me in regards to my previous builds. Plus, bananas can be stacked so I can remove the pins and have more real estate to be creative with mods..
Finally I decided to go with bananas. Function over form. So I got down to the nitty gritty and removed these pins.
FYI There are adapters for Banana to pin plug that Mouser sells.
Here's a pic of a pin plug.
Here's a comparison of bananas and pins. As you can see the holes are quite different in size but the jacks are similar.
Here's what the legendary Scott Lee from Paia says (taken from the Paia Talk forums):
"The pin plugs aren't as readily available as the 1/8" phone plugs, but Mouser 800-346-6873 has them (stk #530-105-0302-1) but they describe them as tip plugs. Mouser has the rubberized test cable too. Solid, 14ga insulated wire wire with about an inch stripped off at each end can be used for the cv patches. Test leads as used on inexpensive multi-testers are often the right size. Since everything in the 2720 or 4700 series systems is on the same power supply, they already have a common ground, so the cables need only be a single conductor wire. When patching to the external equipment, or between a 4700 series analog keyboard controller, one cord will need to be patched between a ground circuit jack (could be a black one?) on the synth and the device ground to establish a common ground between them."