Seems you can just get unlimited CALs.- is there a number of clients already included?
BlackBerry - Enterprise Server Express - Free BES Express Download
No need to. Because if you are on real BES and you have BES licences, you won't be looking at BESx. BESx is for SME and offers much less functionality then "real" BES. The cool thing with BESx is that the user only needs a BIS plan. They dont need to pay their Telco for the (usually more expensive) BES plan.- can previous BES client licenses recycled...
See comparison chart here: