re: Problems with the stick
I haven't been closely tracking the delivered weight of the CEV, so I don't have figures off the top of my head on using existing launch vehicles. I think the heavy lift version of the Atlas 5 could do it.
Good luck getting NASA to use an off-the-shelf launch system.
The payload problem could be fixed by either going to two J2s in the upper stage, or biting the bullet and sticking an SSME up there.