This is a feature we are considering for future development, but as of now, Ultiboard does not have such feature.
If you try to do it with Ultiboard, the answer is, you could... but since the software is not designed to do this task it requires a lot of manual inputs, you need to copy everything several times (panelize) and you'll notice that your RefDes will change, you would need to hide them and manually add text for each component's RefDes, this is the painful portion of the process, as far as powerplanes you'll need to make copper areas instead...
The best way to do it right now, is:
a) Use a Gerber editing tool that will allow you to copy/paste gerber data inside the file multiple times.
b) Talk to your board manufacturer, they usually provide the service to panelize a design.
Nestor