Milla Jovovich has confirmed that that she will start shooting on 'number 4' at the end of the year, and we all know what she's already made three of.
Just ignore the first minute or so of this video, unless you're particularly interested in Milla Jovovich's 16-month old daughter's opinions. What's of particular interest is her confirmation that she will start shooting on 'number 4' at the end of the year. A quick check on IMDB confirms what we all already knew, the only movie that Ms. Jovovich has ever been in that had three previous installments was... (drum roll) Resident Evil.
The third movie, Resident Evil: Extinction, defied the law of diminishing returns and actually made more money that its predecessors and after its release, the producers almost immediately started talking about Resident Evil 4. This comment from Ms. Jovovich suggests that we'll see Alice make a return as well.
Why we'd want to is a completely different question however.