I'm just not sure someone needs to go through this much work (two separate grows) to prove to one person that LED's are good. Why don't you get a couple grand together, set up two identical grow rooms, and test the idea yourself? All lighting systems have pros and cons, and it is up to the user to maximize their grow's potential with what they've got. Lastly, plants under LED seem have different nutrient requirements, so there is no way the experiments could be exactly identical. There will probably always be a difference between the two areas, and some might attribute it to the lights(perhaps different wattages, or brand of LED panel used), but others might question the different nute regimes. Either way, your experimental results will always be questionable. There's no peer review here, and like you alluded, I could just treat the HPS plants like shit and force the LED to outperform. It's like arguing about evolution....in the end it doesn't matter what you think, the results are clear and speak for themselves. LED's work but they will require you to adapt your growing techniques to them, just like a cool tube setup for the HPS is adaptation to the intense heat.
In order to really do a good "experiment," many repeated grows would be needed, and the results averaged. Multiple growers would be nice too. The resources for this aren't worth it when I already get dank buds from my LED.