I did a bit of research and ended up importing it directly from the manufacturer. One has to be a tad careful - there are a lot of spindle manufacturers, but only a handful that really know what they are doing, or care much about the product.
Here is a link to their store on Aliexpress - it’s not exactly the same model that I bought:
The company that owns Aliexpress has the same thing but on a grander scale (called Taobao or Tmall) - and is entirely in Chinese. On Tmall, the Zhenyu company’s shop is much more extensive - here is the link to my exact unit:
To look at Tmall links - I use Chrome, and turn on auto-translate to help make sense of it all.
If interested, its easy to communicate with the sales department at Zhenyu in english - and I just arranged them to send me the unit directly from China, had it in a couple of days.
I have no connection to this company - just a happy customer.
Re the software question: I use Estlcam to generate my threading G-code (and a lot of other stuff). It’s cheapish at $59 USD. Can’t recommend it highly enough!!
Check out his trochoidal milling video:
Or his thread milling video:
I really like how I can chamfer using the same plain endmill after I do a helical drilling op.
Again, no connection to Estlcam, but I really recommend it.