[COLOR="DarkRed"]Does anyone know if the motor and blower fan on this model can be replaced with another brand?[/COLOR]
I do not know but it looks like no one else does either so will add my 2 cents worth and hopefully it will help.

First I would get the numbers off the motor and try Google to see if you can find a supplier.

[COLOR="DarkRed"]Or is there another brand I can replace the fan with without having to tear apart my ceiling?[/COLOR]
There may well be another brand or you may have to buy a new fan and use the parts, still a lot easier than replacing the entire fan.

Remove the fan with it's mounting plate and the blower and take it with you.
Also take a measuring tape.
I was able to get replacements at Home Depot as there is not an electrical supplier that sells these things to consumers in my city.
Motor mounting holes, motor shaft size and shape, blower wheel dimensions and how it is attached to the motor all are important here.

I did 2 fans in my place. On one I had to use just the motor, on the other I was able to use the motor and the blower wheel.
Was a bit of a pain but the plus was that both ended up with a higher CFM.