Change size of pasteboard/background area.

[Grafix Smelter]

I design my graphics artworks in the context of the mechanical front plates and bezels that they live on.
The problem I have is that I loose the bottom of the outlines as the go beyond the page edge as they sit under the page below, so there is no space to place dimensions.

Is it possible to increase the size of pasteboard/background area so the page has a larger distance between the page boundaries.

My current work around is to use a 100x by 100y offset as my 0,0
What would make life easier would be to be able to have 0,0 central on the page, and have symmetrical +/- locations, which is what I do in my a CAD packages.