There are many cloud providers on the market and many more will surely to emerge shortly. One new player - OpSource Cloud - is a bit different (public beta) by providing many enterprise security features.
VPN comes standard with any service and the security can be customized within a multitier environment. Full control over the firewall is also provided and an advanced access control schema. The system is SAS 70 audited and the support ambition is high.
It's definitely an interesting product and will be attractive in some circumstances but I am not sure there is currently enough demand for this solution. Time will tell.