If you have access to a 3D printer and would like to upgrade the working area size of your Makeblock XY Plotter, then follow the link below and enjoy the upgrade!
http://www.thingiverse.com/thing:1448911 (I spent over a month fine-tuning my models prior to publishing them on Thingiverse.com)
I am still working on a couple models for the plotter upgrade but if you already have the XY Plotter, then you are good to go as the other mods I am working on are more for those building an XY Plotter from scratch using open builds v-slot extrusions (or similar) and 8mm linear rods and bearings.
Eventually, I will include laser mounting options so the plotter can cut/engrave via laser power.