There comes a point where one is adding layers solely to comply with an Ivory Tower concept. Having a database instance whose only function is to provide storage for V-layer data makes a lot of sense to me. Have the V-layer talk to that database also makes sense to me. Otherwise, you have the C-layer talking to a V-layer datastore. That is a greater violation of MVC than having the V-layer talk to its datastore.

The issue here is that most developers see the word database and automatically think M-layer. All databases aren't M-layer. For example, where do you place the front-end database that stores sessioning information? That's C-layer, to me.