The one thing that will cause a glass to crack is a pressure point due to unevenness (sp?) in the wood. I just completed building a stand for a 210g out of 2x4 and 3/4" plywood (see the 210 discus build thread started by WhiteDevil). What I did to alleviate pressure points was to use a 3/4" plywood top (similar in construction to your laminate top (3/4" particle board and formica)) topped off with a piece of 1/2" Tuff-R insulation board. The weight of the tank will compress the insulation board taking up any small imperfections in the wood thereby relieving pressure points.
The use of the insulation board doesn't make up for improper leveling or plumbness. To make up for the unevenness (sp?) of my concrete basement floor I have anywhere from a 1/2" to 1/8" of shims between the stand and floor to level it. Also have left to right and front to back cross bracing to keep things in plumb.
To hide the insulation board I plan to use a 3 1/2" x 9/16" piece of trim the top of which will be a hair above the top of the insulation board. This will provide nice covering for the insulation board as well as the cut edges of the 1/2" plywood sides that will enclose the stand.
Raymond Sugel Sr