I want to suggest the Panzer Selbstfahlafette mit 3,7 cm Pak L/70, like the other Test bed armored halftracks with new weapon systems like the Pz.Sfl. II mit 7,5 cm K. L/41 this also was the test of new tactics and equipment. They were in 1935-1936 created advanced Test bed vehicles as a supporting vehicle of the Cavalry regiments.
It also like the Pz.Sfl. II followed the rules of:
very high road speed to achive good operational mobility.
good cross-country mobility, at least the same as tanks.
cross-country speed and maneuverability greatly superior to a tank.
small target area.
good fireing platform for accurate shooting while stationary.
weapons capable of target destruction at rangers of 700 meters up.
cheap and quick mass production in comparison to tanks.
In this case the main point lays in the special version of the 3,7 cm Pak L/45, a version with a longer L/70 barrle and new High velocity ammo. The gun fired an 0,75 kg Apcbc with 1000m/s.
The vehicle was an HL kl 3(H) with a new uniqe turret housing the 3,7 cm gun, an colax Mg 34, AA Mg 34, Gunner, Loader(and Commander), driver and an engine moved to the rear.
It would offer a mobile turreted tank desroyer with probaply the most powerfull (in therms of penetration together with damage) 37mm gun in the game and having armor to withstand mg fire and from distance HMGs. Beeing able to rush to the front, or flak with a powerful cannon, but also beeing easily taken out by heavy guns from even a close distance. A similar vehicle and playstile does offer the BA-11 russian armored car which is allready in game.
Armor: 20mm Front Hull and Turret
Sides and back: 11mm (angled)
Main Armarment: 3,7 cm Pak/KwK L/70 (-7° + 20° vertical and 360° Horizontal)
Seconday Armarment: 2x Mg 34
Max speed 50 km/h
Spielberger, W.J.: Die Halbketten-Fahrzeuge des deutschen Heeres 1909-1945
Ivo Pejčoch - Armoured technique 2
Thomas L.Jentz Hilary Louise Doyle Panzerjäger Panzer Tracts No. 7-1