I'm currently managing about 100+ virtual machines across various ESXi hosts for our development team. I'm curious if possible to have one developer exclusively reserve a virtual machine and others won't be able to access,shutdown, or reset the virtual machine during that time frame. I'm curious if such a application is available already from vmware or third party.
It sounds like you're looking for the ability for a developer to check out a VM or set of VMs, do their work on them, and then either check them back in or discards the VM(s). Is that correct?
VMware had a product called Lab Manager that was geared towards that kind of use. It has been discountinued and replaced with vCloud Directory.
Here's some info to look at: http://www.vmware.com/products/labmanager/overview.html
a nice quick method would be to just create vm folders with permissions for the developer only and migrate the vm in there for the duration that you want to keep a hold on it.