I have temporarily put my 1200as2 into an old's amp heavy case,solid alu,the only thing I did was fine sanding the part witch I should place it with (the lot) of screws and drilled little holes for the leds witch show the various conditions (on the permanent case I'll replace them with 2 multicolors to avoid drilling 10 holes
). It goes warm evenly on all sides but never too hot.
To give a hint of the use,except the easy work on my active setup it has been tested with Virgos,802D,and Maggies 20.7 and never reached the thermal limits.
The new generation of the good class D amps (hypex,purifi,Ice edge) seems rock solid to me as far as I know.