I know this is an old thread but in case anyone finds it useful you can now get borosilicate glass from Qwikfab (http://web.qwikfab.com/accessories/Build-Plate/Borosilicate-Glass-320x320x3). They have 200x200 and 320x320 mm
I wasted time looking for a plate the right size for my Huxley because I didn't realise at that you could cut borosilicate at home with a simple glass cutting tool (got mine from Self Fix around $7). Video showing how is here: [
www.youtube.com]
www.jweoblog.com
3D Printing and Assorted Geekery