In addition to the corporate Test/Stage and Prod farms, I recommend a standalone Dev VM for each of your MSDN subscriptions/developers. Development VMs contain a standalone single server farm as well as all development tools. Any content only solutions (OOB site collection or web scoped) should be configured directly in Production in a new site collection. Custom development (Visual Studio) is completed on the development VMs, released to Stage, tested, and then released to Prod. Each Dev VM should be semi-isolated from the corporate network (separate subnet and domain). Dev VMs should be disposable, distributable, and standardized as in my article here: SharePoint 2010 Development Farm VM
In this way every new developer would only need to copy the VM to their workstation and would be up and running after connecting to Source Control. They would also have full control of their VM so IT admin requests would be minimized. Simply recopying the template VM would fix any issues.
The development VM operating system drive should be a solid-state drive. Optionally, an external BLOB storage and search index partition may be stored on a low cost drive (requires a little more configuration). Workstations must support hardware virtualization.
The Test/Stage servers may need to be used for debugging and development of integration issues. Alternatively, a standalone Dev farm on the corporate network can be set aside for this purpose.
In each case, a process for synchronizing Production site collections back onto the Test/Stage and Dev VMs should be maintained. Usually this includes site collection backups being made available as needed. However care must be taken to ensure information security policies are maintained. This can include scrubbing/redacting content, disabling alerts and emails (this may be done through network isolation), and populating sample data.