A word of caution...
If you put a canopy on top of a rimless tank, it needs to be designed in such a manner as the weight of the canopy is distributed evenly across the top of the tank. You do not want to use a canopy that simply rests on the corners of the tank. This will stress the structural seams of of the tank and could potentially damage or cause seam failure. Most canopies are designed to rest along the entire edges of the sides of the tank, so not usually a problem, but there are some that are designed to rest on the corners and those are the ones that you want to stay away from with a rimless tank.
You also want to put something like rubber bumpers (like those little ones on cabinet doors that keep them from banging) on the parts of the canopy that rest on the glass. Other options might be a felt liner, rubber gasket material, etc... Just something to keep from applying point loading on the glass edge that might result from bits of sand, salt creep, or other foreign matter that might make its way in between the glass and canopy causing point loading. This could cause the glass to chip or apply uneven weight distribution. All things that you want to stay away from.