I talked to him about this a few days ago. He looked and it and we decided not to add VirtualBox tools because the benefits aren't worth the extra complexity it adds to the appliance.
I'd just like to point out that the new VM build contains a lightweight version of VMWare tools. Check it out. Tip: currently, you'll want to use VMWare's OVF conversion tool since there seems to be an issue with using the VMDK as-is. I'm working on that.