Now that is an interesting idea...but having owned a no-roof high-days car myself in the past (Renault Sport Spider) it's such a toy that you buy it to own it more than drive it in the UK at least. The weather is unpredictable to say the least and even a leaky hood is better than none at all.
If you have a passenger (wife/GF!) then you start to wonder about the weather on every journey unless they are a Betjeman-esque "mountainous sports girl" which my wife is not. The AR-1 DB7 (remember that) was a very slow seller (even in the USA its prime market) with no roof where the Zagato Coupe was an instant hit. A speedster could be a real looker but its a rarified market given that its bound to be £100k+.
