Hey George.... back in the day they used Boxwood for their boxing for the most part. Many today use persimmon for the boxing. I don't have access to either but I do have dogwood and it's hard as nails. Persimmon boasts a Janka hardness rating of 2300 lbf, while dogwood has a Janka hardness rating of 2150 lbf. Boxwood is 2840 lbf. 
Both Matt Bickford and Caleb James use quartersawn American beech for their planes. Again I don't have access to beech. But I do have access to Spalted Maple and it's stronger and prettier IMO.
Yes these guys usually ask around $600 or more per pair for moulding planes. Heck... I wouldn't charge that much.
I'm much faster grabbing a moulding plane than using a power router. By the time I set a router up, I'm done or close to it with a hand moulding plane. Like everything else, if you know how to use them and the blade is SHARP! then they are a joy