I would look at Premier Touchless Drying Systems. Just installed one and liked it. The motors are stainless steel and the impellers are aluminum, not steel. Also the cost was inline with other suppliers.
I have a EE Tunnel and have been using the Premier Dryers since I opened in 2005. I have only replaced one motor and housing. They have improved their motor and housing ten fold. I have the old aluminum housing which I can replace with new plastic housing.
The last one I sold had two arches with a total of four 15 HP producers, with two of them oscillating, and it went for around $24,000, with a motor starter box. I would be happy to sell one to anyone and just have it drop shipped.