I use Kicad and I do not know how to draw the vgrooves with it. I've never panelized boards, but I think that this must be the best option for panelizing several same size rectangular ones, am I wrong?
I've seen that there are already some chinese PCB houses offering the no solder mask option, but a transparent solder mask will be much better if is possible, as the no solder mask option can cause problems on SMD boards. This will not only give the boards a "vintage" look but also will be very helpful for early prototypes.