Oh heck yeah there is. Grabbed this from another thread I'd posted it in:
A6M2 Model 21 - As we have now.
A6M3 Model 32 - This was a clipped-wing Zero with an improved engine. Although fewer were produced than the full-span Model 22, using the clipped-wing variant would set it apart from the others more. Additionally, the clipped-wing "Hamp" was encountered in rather large numbers during the Guadalcanal campaign. Whether the Model 32 or 22, however, the A6M3 would be invaluable for the mid-war period which currently substitutes the much less appropriate A6M5b (closer in vintage to our F4U-1A, c.1944).
A6M3 Model 22 - Basically the same airframe as the Model 21, but with the improved engine of the Model 32.
A6M5 Model 52 - The A6M5 could be modeled like the I-16 with several armament options:
- Model 52 - 2x7.7mm and 2x20mm; Mk3 drum magazine with 100rds/gun for the 20mm
- Model 52a - 2x7.7mm and 2x20mm; Mk4 belt feed with 125rds/gun for the 20mm (125rds/gun for all subsequent gun options)
- Model 52b - 1x7.7mm, 1x12.7mm and 2x20mm (as we have now)
- Model 52c - 3x12.7mm (one in the cowl and two in the wings) and 2x20mm
This would especially allow some flexibility for special events, by including early and late armament options. There would be SOME leeway required since the Model 52a and later added an armored windscreen.
A6M6 Model 53c - The changes over the Model 52 were the addition of fully self-sealed fuel tanks and a different engine. The Sakae 31a engine on the Model 53 added water-methanol injection, which would give it a small performance increase (by about 80hp) over the Model 52 because of WEP (the only Zeke that would have it). The self-sealing fuel tanks would also be a BIG change to the Zero by making it less likely to light on fire. Armament and ordinance loadout options are the same as the Model 52c. More performance information SHOULD be available, as one of the three remaining (original) Zeros still in flyable condition is an A6M6.
The addition of WEP and self-sealing fuel tanks should set the A6M6 apart from the rest of the Zeros enough to warrant its inclusion.
And let's not forget the Ki-43:
Ki-43-I- Ki-43-Ia - 2x7.7mm
- Ki-43-Ib - 1x7.7mm and 1x12.7mm
- Ki-43-Ic - 2x12.7mm
Ki-43-III - Uprated engine and drop tank provisions
- Ki-43-IIIa - 2x12.7mm
- Ki-43-IIIb - 2x20mm
Gun package options could REALLY open up a large number of variants. And sorry Plawranc, no 4x20mm on the A6M5c.