Someone overseas did it. I believe it was a group in switzerland with an LS7 or LSX engine.
I'll find the link and post it but it was apparnetly a lot of work and required gutting the engine compartment of nearly everything to make room and all that was removed was relocated to the trunk rendering the car essentially a pretty performance machine but not much of a functional daily driver.
there was a time where I too thought this would be a good idea but I gave up on it.
At least with a V. If I find a wrecked standard STS it might be fun to see what I can do.
A lot of engine swaps for that car are "possible".
I think you have to define what the meaning of the word "can" might be.
Sure, you "can" but it would require spending thousands of dollars to do it and would mean a wholesale renovation of the car's underhood area to accomodate the LSA. It would be a arduous task, indeed but, for the project car builder who likes a challenge, it might be a "rewarding" experience.