I've used some information from the System Center Dudes site in the past for Configuration Manager; however, looking through their current deployment guide, some stuff about storage seems suspect.
One of the things that's mentioned is
Neither the SCCM site nor the SQL database should share their disks with other applications
If you have a VM whose virtual disk files are all being stored on the same block device on your hypervisor, does present multiple virtual disks to your VM really make a positive impact on performance? This question isn't just for Configuration Manager but also for other apps where I've seen guides and documentation talk about using multiple disks.
The example given in the article was a disk for Windows, a disk for the Configuration Manager installation, and three disks for SQL server (one for SQL server and the main database, one for tempDB , and one for logs.
On a system where you had different physical disks, I could see this making sense, and I suspect this guide was written assuming just that -- different physical disks. However, if you're in a virtualized environment, where your VM storage is all on the same device, I don't see where the benefit would be.
Now, if you follow their advice of using 64K cluster sizes for the disks storing SQL data, then maybe it makes sense because the guest OS would be writing to its virtual disks differently (but the data is still being written to the same physical disks as everything else). But it still doesn't seem to make sense to put the Configuration Manager install on a separate virtual disk than Windows.