2 additonal options if you want a smooth wall:
1 - Install DUROCK at the bottom 3 feet of the wall (3x5 sheets). DUROCK can be mudded with a hot mud (EASYSAND) and fiberglass tape. This is the same application they use in a shower transition from the shower base to the walls to create a...
The product is rolling out in phases (see link above)...and the map on the link shows you phase 1 and phase 2. I believe that the plan will be to offer it nationwide at some point.
As for the price...it is less than $0.50 per 1/2 8' sheet more than regular board.
Hope that helps.
You can find the product availability here:
http://www.theweighthasbeenlifted.com/
I believe for now...it is available in the Duluth, MN area...where the poster is from, however it is a regional roll out. Should be able to find it at specialty dealers or Home Depot.
Hope that helps.
I work for USG...the company that invented SHEETROCK...and we have a new product that will likely meet your need for lighter weight ceiling board on 24" oc. It is 30% lighter than regular board and a DREAM to hang. Take a look at the attached for more info...