Tiny private cloud solution

I work in a small company with a few developers. I want to create a small private cloud to allow them to easily create VMs for testing and development (public cloud is not an options). Specifically I'm looking for a solution to:

Start and stop VMs based on predefined images, using Web interface
View and control the state of the VMs
Be able to configure the instances (Linux & Win) using cloud-init or similar method
Basic networking (all machines on the same networkd is perfectly good)

Openstack & Cloudstack seem a bit of an overkill for that purpose, especially due to the fact that I have currently a single server and no plans to purchase more.

Is there any solution out there to such a problem?

Solution

Found Xen Orchestra. It's a Web interface to Xen Server that allows users to easily start, stop and control VMs. cloud-init support included. Unfortunately, the feature that allows users to control their VMs without admin password (self service) costs 500$/month.