Bonsai Nut
Nuttier than your average Nut
Check Forest Farm for the variegated elms and Acer campestre
https://www.forestfarm.com/
I've been in touch with them pretty consistently because they can sometimes get material from wholesale nurseries for me (if I ask nicely). They don't have any variegated U. parvifolia at the moment, and can't locate a source.