I am planning a VCDX defense based on a partially fictious defense. I am wondering if all of the products in the design have to be made by VMWare. I was planning on doing a large desktop deployment based on Citrix XenDesktop using the vSphere Suite as the virtualization environment.
No all the components do not have to be VMware products - running Xen Desktop on top of vSphere is common
You can use what you want. But be prepared on explain each of your choices.