Buick Regal engine to Ford Taurus

Not really. If you had tens of thousands of dollars you could build a Frankenstein.

It would cost a lot more then either a 2001 Buick Regal or a 2000 Ford Taurus are worth. By the time you butchered it into place you wouldn't have a compatible computer to run, meaning an aftermarket hotrod computer setup and wire hanress would have to go in and you'd never make this emissions test compliant (for states that have those).