No I was thinking more along the lines that someone may have designed a rear hatch that could be fitted to the Elise so it look like an Exige. Its for a race car and I want better aero, so I thought if I replaced the hard roof and there was an Exige engine lid upgrade then it would be a cheaper way to go than buying an Exige.
I don't see why it would be so expensive to make an engine cover that looked like the Exige but fits the Elise. You could take the Elise rear engine cover off and just use an Exige style one. I know the Exige wouldn't fit, but I am amazed that no one has done something like that style for the Elise.
The problem with a mass produced engine lid is the fit would never be anywhere near perfect because the Elise wasn't designed for an exige lid. And you'd need to engineer hinges, a catch and associated mounting points. Not really a DIY type job for most people. EliseUSA had a drawing on their site a while back of an Exige style hatch, not there now.
It shouldn't be too hard to fabricate such a thing from fibreglass - it wouldn't be transparent though (that would significantly add to the cost and complexity). As noone has done it to date you have a new market!!
PS: simple fabrication for use on a race car rather than street car (avoids need for standard type hinges and catches - you'd use pins)