I looked very seriously at a Boxster the last time I was car shopping. There's just no way to pile a serious amount of crud into that car. I just drove to Dallas last weekend (~4 hours) with my PowerMac, 23" monitor, travel bags, and came back with all that plus a crate full of CDs. Sadly, none of the two-seat convertibles have that kind of space. The Z3 Coupe was just exactly what I needed... on paper...
As to Corvettes, I'd say the correct answer is the Pontiac GTO (a.k.a. Holden Monaro). I saw one at the Houston Auto Show and I was impressed. They wouldn't let you sit in it, but it looks to have a significantly improved interior relative to the usual GM fodder, and you've got Corvette guts.