That's a pretty cool idea. First time I've seen it. It definitely frees up real estate for fancy headstock inlays. I wonder what the guides through the headstock are made of. It would take some precise drilling to get the positions of the guide holes on the back of the headstock to be accurately and evenly located because of the angle.
According to this Gotoh web page
http://g-gotoh.com/international/product/st31.html, with the tuners that are configured with the post on the same side of the headstock as the gear housing like in the photo above, the maximum tension is only 22 lb. So that would rule out most steel string sets. (See the second note under "Function" referring to Fig. 3 on the web page.)