BN (Greg?)
I can suggest two things.
1) Vans Pines Nursery. I worked for a nursery where we ordered pines and other conifers from VPN
to use as grafting stock and for 'growing on'. Their prices are great, the product excellent. They sell
one, three and five year old seedlings in addition to more mature plants. You will have to order a sizeable quantity but in my opinion it is worth it in the long run. You can't really expect varieties as these typically come from sports, witches brooms and the like and are propagated by grafted. Pine seedlings are more often than not the secies only. Your local forestry service might yield some results as well. I ordered five-hundred short leaf pine (P. echinata) and Eastern white pine (P. strobus) for a mere twenty-five dollars each. Cheap and worked out well as having that many seedlings left me with some of each after the squirrels destroyed a large number of both species.
2) Order seeds from J. L. Hudson, F.W. Schumacher or Sheffields (they are the most expensive of the three, and for no reason that I can discern). I have been raising pines from seed for a few years now and find it very rewarding and hyper-economical. Highly recommended.
Nigel