Adobe actually offers their .msi through their website. You have to sign up to be a distributor here and it takes them a few minutes to confirm your verification email. They email you a temporary link which contains a download package. You can read further here about how to extract the .msi package from the Adobe download.

Once you have the .msi and .cab files, etc., in a directory I then used this command. This is the same command as used with the Firefox package.

msiexec /i "AcroRead.msi" SETMULTIUSER=1 /qb"

Adobe Reader 9.0 .msi package