I have used Toluene as well for bonding plexiglass, i found out the hard way that it well effect plexiglass when i used it to try and clean tape residue from a high voltage plasma globe driver that happened to use black plexiglass for it's cabinet, oddly i think i have chloroform, i know i had some in the past but the police took it (long story there) Methylene Chloride will bond a lot of plastics as well. I used Toluene to repair a tank on a humidifier with a sheet of plexiglass and aside from a few air bubbles it worked out ok. unlike glue all these solvents turn the plastic to liquid then re hardens when the solvent evaporates off
As for using black plexiglass to hide the power supply, I don't see any problems with that as long as you have the ventilation holes, the now badly melted case to the plasma driver works very well and that sucker puts out over 20kv. I have also used it for cabinet parts, if the power supply got hot enough to effect the plexiglass i think you would have other problems
Remember Remember The 8th of November, When No One Stood, but Kneel, In Surrender
In a popular government when the laws have ceased to be executed, as this can come only from the corruption of the republic, the state is already lost. Montesquieu