http://en.gentoo-wiki.com/wiki/VirtualBox#Run

getting tap devices to work correctly http://hardenedgentoo.blogspot.com/2010/04/kvm-setup-with-bridged-networking.html

VBoxManage convertdd hdb.img hdb.vdi
VBoxManage modifyvdi /usr/local/vmware/WSUSR2_KVM/hdb.vdi compact

VBoxManage setextradata XPSP3_VBX CustomVideoMode1 1920x1080x32

Resize

VBoxManage modifyhd /usr/local/vbox/WSUSR2_VBX/hda.vdi --resize 40000

Create a vm from shell (headless)

VBoxManage createvm --name "test" --register
VBoxManage modifyvm "test" --memory 512 --acpi on --pae on --hwvirtex on --hwvirtexexcl on --vtxvpid on --boot1 dvd --nic1 bridged --nictype1 82540EM --bridgeadapter1 tap0 --ostype Gentoo_64
VBoxManage storagectl "test" --name "IDE Controller" --add ide
VBoxManage storageattach "test" --storagectl "IDE Controller" --port 1 --device 0 --type dvddrive --medium /usr/local/install-amd64-minimal-20140403.iso

VBoxManage storageattach "test" --storagectl 'IDE' --port 1 --device 0 --type dvddrive --medium /usr/share/virtualbox/VBoxGuestAdditions.iso

VBoxManage startvm "test" --type headless
VBoxManage controlvm "test" vrde on

VBoxManage createvm --name "MX" --register --basefolder=/usr/local/vboxssd
VBoxManage modifyvm "MX" --memory 2048 --nic1 bridged --ostype Fedora_64 --cpus=2 --accelerate-2d-video=on --bridgeadapter1 enp4s0
VBoxManage storagectl "MX" --name "SATA Controller" --add sata
VBoxManage createmedium disk --filename /usr/local/vboxssd/MX/sda.vdi --size 40000 --format VDI
VBoxManage storageattach "MX" --storagectl 'SATA Controller' --port 0 --device 0 --type hdd --medium /usr/local/vboxssd/MX/sda.vdi 
VBoxManage storageattach "MX" --storagectl 'SATA Controller' --port 1 --device 0 --type dvddrive --medium /usr/local/samba/iso/Fedora-Server-netinst-x86_64-37-1.7.iso 
VBoxManage modifyvm "MX" --vrde on --vrde-port 3391 --vrde-address 192.168.99.2