The inspiration for this circuit is the fantastic Synbal project from “Electronics & Music Maker” magazine in 1983.
So by pure coincidence, today’s mail contained, among many other things, a mini module with the noise and “metallic voicing” sections from the Synbal.
I guess I should have posted this to the mail thread before I started building, but I’ve been optimizing my build process lately and got a bit carried away 
(need to do some tests before I populate the noise section)
EDIT1: It works! The tuning voltage range is larger than expected, though, so something’s not working as expected. Or I cannot math. Probably the latter.
EDIT2: Oops, the noise generator has a “have you tried turning it off and on again” issue. Stupid capacitor left behind from an earlier iteration (one more thing for the checklist, I guess). Bodged on an extra resistor, and now all’s well (need to tweak some levels, though).