Along the lines of the Rome mentioned above, K2 has the Conda system in several of its boots, which has a BOA the cinches around the ankle on the liner. I hesitate to recommend the K2 boots since they material on the heel of the shell sloughs off almost immediately (There is a thread about it somewhere). In addition to the Conda system traditional lacing, they have a boot that has a triple Boa, though it is really stiff.
The Vans Revere and Infuse have a Boa that tightens down around the tongue of the boot at the instep, which should help hold your ankle. I've heard good things about the Infuse, but they don't seem to be in stock anywhere. Wiredsport posted some pictures of next season's model. I think I'm going to look into those, since I've been unable to find boots that eliminate heel lift as well.
Also, consider boots with articulated cuffs at the ankle or semi-articulating cuffs at the ankle. It seems that boots without articulating cuffs suffer from shell distortion, which causes the shell to widen at the ankle when you lean into a toeside turn. I think most bootmakers try to mitigate this with locking the ankle in the liner. I was tried on a ThirtyTwo Binary Boa (dual Boa) and they were pretty comfy, but I have narrower ankles and wasn't sold on whether I would get heel lift.
If you don't already have some, get some custom footbeds. In addition to helping with foot cramping, they may also allow you to fit into a smaller boot, since as with most factory footbeds, your foot sits flat and is longer and fatter than if it were in a foot bed.
In my quest to find boots, which is ongoing, I found that, in the beginning, I was ending up with boots that were way too large. I wear a 10-10.5 street shoe, but am wearing a 9.0 Burton Ion (probably could fit into an 8.5) and a fit into a 8.5 K2 with a little tightness in the toes that probably would go away if I heat-molded the liners and after they pack out a bit.