QuestForCure, I can't help you with Apotex; they didn't sell much of their product last time they produced it. A lot of their problem is in the way they market it; and it sounds like you've identified that.
From everything I've seen on Apotex generic, it's priced way above Roxane, and Mylan, and just slightly below Colazal. I've never had to use it, but it does look like it has different fillers than the other two generics.
Colazal is being shipped directly from the manufacturer to the wholesaler, and will be in some pharmacies by late next week.