It can be done:
The Renault Espace F1 uses a Williams F1 V10 placed in the middle of the rear seats!
But I don't know if it could be done practically as the heat and NVH issues should make it an engineering nightmare to reduce to Toyota Camry levels. Then there's the intake - where will the air come from if you put something over it (I'm guessing it's not going to be left uncovered)? Does it get piped in? It'll also be a nightmare to work on for your mechanic.
But with a few changes.... (runs off to AutoCAD)
I'm dropping out to create a company that starts with motorcycles, then cars, and forty years later signs a legendary Brazilian driver who has a public and expensive feud with his French teammate.