[Glass build plates]

sxt is that where you got yours? You really think it needs to be tempered? I read a couple of blog entries that said make sure it's not tempered. One of the reasons I wanted to go water jet is so that I preserve the stock slots. I'll email those guys and find out if can do that.

Didn't think of the frosted glass.. I wonder how that would work. Might be worth a test and find some cheap thinner frosted glass and slap it on top of the acrylic.

Sorry for the late reply, I totally forgot to click on "notify when reply posted". Yes, that is where I got mine. They are pretty quick and I got it was exactly as ordered. I like them because they specialize in one-offs and they do ceramic (tempered) glass or all shapes, thicknesses and sizes + they can drill holes in tempered which is rare.

I would advise going for tempered. It's not the actual temp that the glass rises to, but it's more about the speed at which it heats up and cools down that can cause cracks.

[Glass build plates]

I already got a glass build surface (not for Ultimaker, no ultimaker yet actually..), but did you check onedayglass.com? They are in the US, have reasonable prices for one-offs, they do tempered (which I would highly advise) and can drill holes too.