Perforce Helix might be even better - it even has a DVCS model based on creating a "local server" that can fetch/push from a shared server asynchronously from u

Perforce Helix might be even better - it even has a DVCS model based on creating a "local server" that can fetch/push from a shared server asynchronously from use of that local server, and a hybrid model that allows for only parts of the repository to be hosted on your personal server, and other parts to follow the more traditional Subversion-like model. Things like exclusive locks on files that can't really be "merged" are also supported (for example, all your assets). The only downside is that it's not open-source, and as a result has a much smaller community. It's free for up to 5 users, then "email us" for any more. But if a very flexible VCS model is something you need, it's the same as anything else you need to pay for. Google used to use Perforce until they hit a certain scale, so it's likely it'll work for you until you hit that scale and can build your own tools too.