An M10/Achilles/M36 (if that's what you're thinking about) would be a very popular kit, I'm sure.
The problem with an M10/M36 kit is that the M10 was built on the diesel-engined M4A2 chassis, while the M36 was built on the Ford petrol-engined M10A1 chassis (many M36s were rebuilt M10A1s - the M10A1 itself never saw active service). So there are detail differences on the engine deck and rear hull.
That issue aside, it's presumably possible to fit all the parts onto the sprues - you did something similar with the M4A3 (although I realise that the M10 and M36 turrets need different interiors as well as different turrets).
The Achilles used the later M10 turret, with the 'duckbill' counterweight on the rear. There were internal differences between the Achilles and M10 turret, but they're probably easy to 'fudge' if the detail is simplified. The most inconvenient difference between the Achilles and the M10 is that the Achilles lacked the prominent bolts on the turret and hull sides, intended for applique armour (that was never fitted). These bolts also disappeared from very late M10s and M36s (but remained on the hull front), but most vehicles that saw service in WW2had them. So I guess if your kit was based on the late version of the M10/M36, you could omit those bolts.
