Bimotas are typically expensive as they are truly built by hand by a few guys in Rimini. Nothing like an assembly line exists.
Twist the Throttle- Bimota Pt. 2 - YouTube
The MSRP on a DB6 is somewhere between 30 and 35k depending on the model. Used ones turn up rarely but I have seen 07+s pop up starting around 15k. You can usually expect those to have very low mileage (under 3k) as it seems most owners either have multiple bikes or don't ride them much.
Extremely rare and the details on the bike are artwork. The good news on the modern Bimotas is that the major components are well known and serviceable including the tried and true Ducati powerplants. I wrench my own bikes so aside from specific body parts most maintainable items are available from Ducati dealers or aftermarket suppliers.
There are some interesting differences. Different ECU with different fueling profiles. No immobilizer, no stepper motor. Otherwise the drivetrain is just like what I am used to.
One thing for sure, you usually won't see one at a bike night unless you bring it.