You might also consider something like this if you want something lightweight, portable, and highly adjustable. Adjust the height as well as the angle.
It's for a hammered dulcimer. I got one long ago, unfinished, as a kit, very inexpensive at the time. From a company called "Lark in the Morning". (On checking I now see that they don't carry this design anymore. Though they are a dynamite resource for unique ethnic and unusual instruments you won't find anywhere else. Do you have an "Aboriginal Cricket Whistle" that sounds like a real cricket? I do.
You never know when you might have to hunt crickets. You need a really tiny gun too.)
In any case, I found it doubles as an excellent keyboard stand, for play while sitting at any height or while standing. That's why it was designed this way for hammered dulcimers.
I think your best bet at locating one would be doing a Google search for "adjustable hammered dulcimer stand". If you want, add the word kit after that search string. I notice from that search that you can even get the parts-plans to make your own from scratch.