That's a good article.
But when you use glass as the frame on top, do you attach it on its short side, like the Euro bracing? Or?
You wouldn't have to brace the sides, just the front and back panes, like Euro bracing. The 8" long sides wouldn't be subjected to much bowing where the 20" front and back would, so they would need the Euro style bracing on the top... if you're not planning any other kind of brace. Another thing that would work is just a single strip across the center of the tank, connecting the front to the back, which would prevent either from bowing out. Just remember how fragile this single strip would be. If you hit it with something, it could easily break and fall into your tank. As long as these are going to be low maintenance tanks, like for a Betta or something like that, they would probably work but I wouldn't want to start hanging stuff on the sides and having to fool with them all the time.
BTW... I speak about this from experience of having worked in apartment complex management and maintenance and having changed MANY window panes and seeing how easy this type of glass breaks even when trying to replace a broken pane, if in a hurry.
EDIT - Ahhhh.. I see you added some pics while I was typing the above. Did you silicone the 10" cube yet? I don't see any so I was curious if you did that good of a job? ;-) Or is it just taped together for now?
With 10" sides, they shouldn't bow much but to make this stronger and also impact resistance the corners, adding a frame around the top and bottom would be a good idea. Just some firring strips, maybe 3/4" wide by 1/4" thick, and then either stained or painted and then siliconed to the top and bottom, would add strength to prevent bowing and also add protective bumpers for the occasional accidental bumping of the corners so you don't have corner breaks.
I should add that having the wood stick up a little above the top of the tank and then running a bead of silicone along the top of the glass would also prevent cuts... just use a tool when smoothing the bead since the inside edge of glass will cause some nasty paper cuts to your fingers if you used them. ;-)