They can be purchased through McMastercarr. This is the first time I have heard of this so not sure it is worth stocking as an accessory item. Here is the part info:http://www.mcmaster.com/#roll-pins/=fyma2fSlotted Spring Pins
Use these versatile pins for fastening, pivoting, and holding. Ends are beveled or rounded to aid insertion. Actual diameter is slightly larger than the diameter shown, allowing pins to fit tightly when installed. Wall thickness is approx. 20% of the diameter. For the best fit, your hole should be equal to or slightly larger than the diameter shown. Breaking strength is measured as double shear, which is the force required to break a pin into three pieces. Meet ASME B18.8.2.
18-8 Stainless Steel—The most corrosion resistant. May be mildly magnetic. Not rated for hardness.
For technical drawings and 3-D models, click on a part number.
18-8 Stainless Steel
Strength, lbs. Pkg.