The March 1998 issue of Small Arms Review had an article on .22lr machineguns and subguns starting on page 32.
In the open bolt category they reviewed the American 180, a Group Industries Uzi, Voere (which was imported as a semi-auto open bolt and converted, prior to 1986) which looks like a standard hunting rifle,
Closed bolt 22lr machine guns included the Norrel/Ruger 10/22, Bingham PPsh-41 22lr, Trejo 22lr machine pistol, Max Atchison 22lr conversion kits for the M16, Ruger AC556/22lr conversion by Ceiner, FAL 22lr conversions by H&K and Erma, Fleming M11 & MAC 10 22lr conversion kits, Sentinel MAC 10 22lr conversion kits, MP5 22lr conversion kits and Numrich Arms 22lr Thompsons.