Hey Cap'n...
Well, while waiting on a Client to send some info for a Show Contract, I knocked this together for ya in P-Shop... And of course, I JUST realized, that this is WAY over-done
(for such a little module; I mean, this is not a 400lb. 500W KTP death-ray that needs support!
)
...You could simply use the holes I 'put-in' for the 'proposed' clamping screw-locations
(both sides of the diode, in the comp) AS the holes for the 'posts' to slide-thru, and then, the 4-corners would
still be for 'clamping' screws, as-in your original design, which is clearly better
(more 'evenly clamped'...)
And, of course, the idea would use nice, 'beefy' posts that JUST barely clear the 'pass-thru' holes,
NOT like I show here, all 'loosey-
goosey'
(this is after-all, just a 'quickie comp' to show the idea...)
Anyhoo, fairly simple, and should-not add 'exponentially' to the cost... And yes, I realize this 'kills' any pan / tilt / rotate ideas...

just a quick doodle for a simple height-adjustable version, sent in peace...
PS - for 'extreme' height-versions, you can simply offer 'variable-height post kits', ie: 3", 4", 5" etc, to-beam-center, etc...
'Ivan & Co' have both, just sitting collecting dust in Van Nuys... not sure of 'operational status' but I can certainly ask, if you'd like...

just lemme know... PM or ring-ring...
...Perhaps a part-cash / part-'credit-towards-purchase' dealy-o ???
(c'mon, you know I am a kinniving-little sob!! 
Anyhoo, will be keen on your thoughts and your thoughts...

j