The AT-X 840 is usually mounted on the A700, in the Tamrac Velocity 8x Sling Bag. I currently do not have an external LowePro case for it. I believe a LC3 just might do it, but I still have to test it.
The TAMRON 70-200mm is in a LowePro LC4, that wrote about earlier (see this LINK)
You will also see the very case that TAMRON includes for the 200-500mm.