The problem with all these awesome dovii being shown in no one is actually measuring them. Granted, that can be a very tough thing to do in most circumstances, but without a measurement it's all assumptions.
When I first saw Mel's dovii I was positive it was at least 24" More like 26". 150% positive. But after discussing it and holding objects up to him next to the acrylic, I was 200% positive he was at least 20". Then after measuring said objects that we held up to him...it was pretty apparent that he was more along the lines of 18-20" tops.
Taking the photo Greenterra posted, I assume that is a devil pair. Larger male behind and female in front. A VERY good sized female is 10-12". So we'll say 12". She appears to be facing away from the camera at an angle while the dovii is facing the camera at a similar angle, so we don't need to adjust any numbers. I measure her at just under 1.75" on my screen. The male dovii I measure at just under 2.75", which assuming the devil is 12" would give the dovii a length of just under 19". Quite a bit different than the 28"+ guessed by Greenterra. Am I saying the dovii is 19" vs. 28", of course not. But without actually measuring we'll never know for sure. I over estimate all the time.
I'm 6'2" (74"), that means that dovii, if 28" would be a few points under 40% (37.8) of my height, or the length of my outstretched fingertips up to my shoulder.