KJC

Take a trip to some HVAC shops. A lot of older furnaces that are being replaced have working fans in them. Some of those fans will have a belt drive and keep the motor itself out of the air stream. Even if the motor itself is shot the squirrel cage fan is there yet. Put on a new motor. Nice part about these fans is they have serviceable bearings. Move a lot of air and most HVAC places will sell 'em for scrap price.