So last night I read this thread. I honestly had never heard of or seen a Japanese Maple trimmed in the manner of your pictures. Sure enough a client asked me this morning to take a hedge trimmer to a neglected 50 year old jap maple in his front yard. I just cringed and grabbed a saw and my felcos and did it the right way. When it comes to trees if i wouldn't do it in front of my arboriculture professor I wont do it.