Ive been told they have different sizes, and are around $5. Have rounded edges, and have 200mm squared and beyond at the actual physical stores.
http://www.ikea.com/us/en/search/?query ... ting=price
I havent picked one up yet, but I was told by someone who uses them in their videos that they get them from IKEA. Also if its a standard mirror, they should be easily drillable with a spade bit/glass bit. So instead of placing them on top of the existing acrylic printing bed, it should be possible to drill the 4 needed holes and replace it altogether. Or you could just place them on top of the existing bed lol
It would also not be too far fetched to think that 4 studs could be jb-welded to the bottom of the mirror instead of drilling it.
Here is a snippet of advice from another internet user in regards to drilling glass/mirrors.
You can purchase glass drillbits at larger hardware stores. I make a ring out of putty around the area I will be drilling in. Pour in a small amount of isopropl alcohol for cooling the bit. Drill with light pressure. I have also added a small amount of salt in the alcohol for more abrasion.
Im going to run to IKEA later and see what they have in stock. Figures they would carry something like this.