I may be a little late here, but oh well!
I too am considering starting my own tree nursery on my land (even though I am sure it won't happen for several years!). I am a landscaper by trade and training, so I guess I know a little more about it than you might?
At this time, I am leaning more towards a "pot-in-pot" type of operation. This will limit my need for equipment (renting a skidsteer and tree spade at about $500/day makes that decision easier) and makes trees available year-round. Trees that are actually planted in the ground can only be dug in the spring and fall. The only problem with a "pot-in-pot" is the potential for circling roots. If you are turning your inventory over fast enough, this shouldn't be a problem.
If you are not familiar with this type of propagation, it is (very) basically a liner pot that is permanently installed in the ground and then another pot is placed in the liner pot. The second pot is then filled with soil and the desired plant.
Other factors to consider are weed control, irrigation, transportation of the sold trees, and labor to plant/dig the trees.
There should be a wealth of information out there about pot-in-pot propagation, just do a search on it if you are interested. It's a relatively new system, but I think it will be the future of the industry.
Dan