I had to mull over this question when my original Elan was rear ended by a Jag.
I considered a few options: Porsche 944, Alfa GTV, many of the 3 series BMWs were great. The Fiat Coupe 5-pot turbo is quite amusing and the newer (up to 2005) 190bhp Celica is surprisingly light and fairly punchy.
Apparently you can plonk the 190bhp 1.8l lump from a Celica/Elise into the newish MR2 Roadster, which weighs less than 1000kg. With some tweaks this might be the basis for a half decent modern Elan replacement, except that you'd still have to make do without a boot!
In the end I gave up and found another Elan. It's not perfect and in hindsight buying a car like this in a rush is a big mistake, but nothing else could quite provide the same package. I'll be very sad when I can't have one anymore.
Adam


