I purchased my supplies from David Pike. He runs the website kintugi.com, and sells everything you need on the Etsy store under the name KintsugiSupplies. He was very helpful and provided all of the instructional information I used to get started.
Another source I have identified is mejiro-japan.com. They have much lower prices, but I haven't yet tried ordering from them, so I can't vouch for quality or customer service.
Humade is a Netherlands based company that is marketing what they call new kintsugi, which uses two-part epoxy with an additive that makes it look like gold. I have not yet tried their product, but it appears to be an interesting option for those who want to try Kintsugi without committing to the long multi-step procedure.
Many of these edibles are from Chef Rubber, which has a wide selection of professional chocolate and other specialty cooking supplies. If you order from Chef Rubber or any other chocolate supplier, DO NOT BUY "DECOR" PRODUCTS! They are not edible and intended for displays!
These powders are for dusting onto the melted chocolate in order to accentuate the repair.
These can be used directly for repairs, so additional powder is unnecessary.
(chocolate has lost temper by this point)
White/Milk: 105°F/40.6°C
Dark: 115°F/46.1°C
(chocolate will have regained temper if it is properly treated while cooling to this temperature)
White/Milk: 78°F/25.6°C
Dark: 80.6°F/26.7C
(chocolate is easy to work with and maintains temper)
White/Milk: 84-86°F/28.9-30°C
Dark: 88-91°F/31.1-32.8°C