Whereabouts are you located? And are you planning to have them installed? - these would be big root balls, likely B&B trees.

I live in city of Atlanta. Yes we would have them installed and plan to use as screen. i like eastern red cedar appearance better than cryptomeria or leyland. i hope they will attract birds and chase away mosquitoes. Hope to mix some holly into the screen as well.

You can try calling Rex, or Sauls (and ask for the Tree division at Sauls) to get larger sized trees. They both typically sell large plant material to builders and developers. I have not purchased with Rex, but I have purchased and installed large trees from Sauls for clients, and the clients have been very happy with their trees.
The other option is Harps which typically only sells to retailers but you may be able to order and get a delivery to a local store who stocks their products if you call and ask. They are generally very flexible and can be found under Harps Farm Market.

John C. Calhoun, South Carolina's most famous antebellum politician, married his cousin Floride Bonneau Colhoon, a native of the Low Country, where malarial mosquitoes were commonplace. Fort Hill, Calhoun's plantation house, now the centerpiece of present-day Clemson University, is surrounded by allees of Eastern red cedars, which Floride planted in the early 1800's, with the belief that they would ward off malaria. Today, this theory is considered an old wives' tale--not to mention the fact that malaria was restricted to the Low Country swamps and generally not found in the South Carolina Up Country.

The Georgia Native Plant Society is trying to sell 3 of them that were used in a flower show exhibit last month. From soil level to tip, they are 6-7 feet tall. They are B&B and have a large root ball.

If you are interested, let me know and I can send you a link to pictures, but you can see them in the background here.

Here is a link that might be useful: Picture