Personally I choose to display my headgear on vintage hat blocks for a number of reasons- they are anonymous, they are vintage themselves, and they don't fight for attention with the piece they are displaying.
I do however have one semi-lifelike display head which is new but modelled on an original plaster version. I bought him from an Ebay Seller in the States a few years ago as I was thinking of displaying this way. I believe this company also did heads and torsos. If anyone's interested i'll try to look them up. He has moulded hair but it never occured to me that it might not work with a helmet and it doesn't seem to be a problem. I actually prefer this to the terrible wigs I often see used as this is slightly abstracted and we all know it's a mannquin. I think he really has the look of the period and does great service whoever's kit he's wearing. I've decided not to use him full time as I prefer the abstact nature of the blocks but he's excellent for showing off how an item looks when worn.