There's no data on the BES that should be changing (assuming non-local SQL). We did an online P2V without issue a couple months back. Go for it. It was easy. You can always roll back to the physical box.
I have seen SQL use a bit of resources in a VM.
Most use a dedicated SQL server for it or place it in a diff VM.
SQL express is free and works fine with BES
__________________
I had to fall
To lose it all
But in the end
It doesn't even matter
I was asked about SQL by the P2V guys, so this is probably something that is going to be taken into account. I'm not directly involved in the P2V - I'm just the BES admin.