I currently have three KM A bodies with KK133/SBK capsules (some of the first made, supplied by John Willett in his day job - thanks John) and three KMA bodies with KK143 capsules plus three more KK143 capsules. But I have a lot more KM100 series bodies, capsules, and accessories, and will probably be looking to top up on bodies and accessories if there are any bargains to be had if any shops look to dispose of stock of the old system. The adapter rings to allow AK capsule to fit KM A bodies are good news. I'll be looking for some of those when they're available.
On the dimension discussion - the KM A body + capsule tends to be bigger (longer) than the equivalent KM100/AKxx combination due to the KM A body being a lot longer than the old KM100.