If they announced a limited run of 100 trads. With say a 2.3 Duratec with around 200bhp. Narrow track, light and simple, they would probably sell the lot.
I'm not sure overcomplicating the suspension is worthwhile. It may not even be possible for type approval. The sticking point might be the rear axle, but Caterham still use a live rear???
Obviously price point is the issue. £40k would be amazing but £55k is more likely. It will never happen, but I would certainly look seriously at such a spec.