According to Spielberger [Sturmgesthutz & Its Variants,pp 13-18], the Reichswehr employed commercial available Hanomag WD schlepper [tracktors] with 37mm mounted and a couple with 77mm FK 96/16 as training vehicles for the 'Kraftfrabteilungs'. Usually one company per battalion.
These weight ~ 6 tons and could do 6 kph which is fine for following Horses or troops or bicycles? But by the 1930s these battalions would convert to motorcycle battalions.
Since there were 3 kavalry divisions each with 6 kavalry regiments thats about 18 kompanies... maybe 100-200 WD tracktors in service.
Christopher Chant [World Encyclopedia of THE TANK, pp 106] reports that initial plans were to order 289 x "Leichte Traktor" [37mm gun turret] in the early 1930s, but was eventually replaced by an order of 150 x LaS training traktors ...which were essentially Pz-I chassie [open top with no superstructor or turret]. That ofcourse was followed by the order of ~ 1400 Pz-1 tanks starting in 1934.
According to Speilberger the an alternative to the Hanomag WD tracktor was the 9 ton Krupp 'LSK' fully tracked vehicle with a 77mm FK 96/16 , mounted up front in an open topped configuration with no side sheilding. This vehicle was not produced but looks alot like the 'LaS' AFV that would later become the Pz-1.