Neither lotus or Ferrari are offering a modern underpinnings with a pre-war body, my point being that the attraction of a 4/4 or other trad is MMC give you the whole vintage package, coach built body,stiff springs and a flexible chassis albeit with an engine and brakes fit for current road conditions, at mid market money. If Morgan engineered a modern stiff chassis for the 4/4 I wouldn't buy it because 1600cc/120 bhp and £35000 wouldn't do it for me.
I agree the Roadster is pushing the current configuration but you are moving into a different price bracket, and a +6 version of the new +8 would have a lot going for it.