When you setup environments in the cloud, you essentially buy what you have setup. AWS, Azure, Rackspace etc are all giving customers software defined routers for internet breakout. Sure they have physical equipment above that, but that is essentially your ISP.
The best example of what you are doing would be AWS with NSX or OVH. Your just doing it locally and not buying it from a cloud provider.
NSX won't be as feature rich as other venders that specialize in certain areas (F5 for Load Balancing as an example) but will do all the basics well. If you are looking for internet breakout, IPSec VPNs and Load Balancing then NSX should be a good solution.