Mission: IFR cross country.
Performance: 250-300Kts at FL25
Seating: 5 (two in front, bench or 3 in back)
Cost: free, of course. Barring that, <$100k US for build
Kit for wings/canards, etc. Plans or QB for the rest
Single engine, IO-540 or smaller.
Fixed gear, including the front (no grazing)
Pressurized cabin.
Sounds a lot like a Velocity XL5, I guess... but different.