Koshi Chimes I bought my koshi chimes from various sources. Just google and find the closest retailer. One source worth mentioning is Hokema, they also sell other sound healing instruments like the Sansula:
Koshi Gong Stand This is the official website of the company that builds them - Studio Gong: http://www.gongstands.eu/en
Ebay This is the ebay listing where I bought the gong stand on ebay: https://www.ebay.com/itm/Solider-Buchholz-Koshistander-40-cm-NEU-GSTP-40K-Harmonie-/332022503063?hash=item4d4e155697:g:MtAAAOSwImRYHEy0
DIY You can also use any gong stand and just add the 4 hooks for the koshi. Or start from scratch and build your own - or ask a local carpenter to give you a hand.
There are three kinds of Sansula - Basic, Renaissance and Deluxe. What is the difference?
So, I own a Renaissance Sansula and think it is the best choice for most people. You can order them directly from Hokema https://www.hokema.de/en in a variety of different tunings with a bag and an aditonal tuning hammer. There is a variety of tunings for this instrument and I use Heavenly A.
A little company in Wales, UK makes stunning high quality Shruti boxes. They also supply bowring foot pedals, so you can play guitar AND Shruti at the same time for example - pretty nifty. I am not aware of any other source that provides such well made instruments of this kind. The Shruti boxes from India are not always good quality or exact in tuning and when you want to play together with other instruments, this can become a problem. The Shruti Box M1 is a small and portable instrument (about 2,6kg) that can be used for yoga, kirtan, or meditative music sessions.