Although not really a Flight-Sim, ArmA 2 has the pilot modelled in cockpit, but nothing except instruments is animated so it is kinda spoilt...
Although +1 for this. And I honestly don't think that polygons would be an issue, pilot model could be made for probably under 1000 poly's with a decent 512x512 texture map + normal map - and of course all could be availible as an 'option' but like it's been said, the devs really wouldn't care which imo shows a lack of motivation in their own product.