Are there any livecds/liveusbs with virtualbox or vmware (or similar) installed on them? I wonder if i could have livecd with virtualbox which i could use to boot my vdi images without configuring host...
You can re-master a custom livecd fairly easily these days from most distros.
Up to date info should be available for your chosen distro.
A few resources - probably out of date
Successfully remastered livecds with vmware-server-1.x on Fedora, Mandriva and Debian.
Successfully remastered livecds with virtualbox-3.x on Opensolaris, Mandriva and Debian.
Vmware-server-2.x is a pain on livecds because of the virtual machine inventory. Works as a rescuecd as long as you don't save any machines in inventory for a reboot. Both vmware-server-1.x and virtualbox-3.x work well with livecd + USB flash for updates/reboots. Virtualbox-3.x works well in textmode to save ram/cpu, accessing virtuals remotely using RDP console or tcp services.
Highly recommend using dual boot and build a minimal system for virtual only use. Our main use is utilizing un-manned CPUS. Plug an Esata external drive into an unused machine. Boot to the partitioned Esata disk containing a small textmode OS and virtualizer on a small partition and another "data" partition for virtuals to make use of machines without touching the internal hard drives.
Knoppix v6.0.1 has VirtualBox OSE (open-source edition) installed. It is found under 'System' in the LXDE menu.