Hi Greg,
nice talking to you yesterday!
I see that they have the "Raagini Digital Tanpura Machine"
It's a little costly but considered to be the best (
).
I saw (heard) it used at the conservatory in Madras.
The box is a sturdy metal one, you can use a wall wart or
batteries. Line output is a mini tele jack but that seems to
be the standard for all these products.
Another brand is "Radel". I got one of those and am regretting it 'cos
the sound is not that good and a plastic enclosure. Was cheaper though...
If you just need to get the sound into your DAW
its easier to use samples I think.
For live use on the other hand these boxes are very handy, with
standard tunings and possibility to tweak on the fly.
Best,
Anders