You also have to differ between the Japanese KC-767J and the Italian KC-767A. The KC-767J got no pods for hose-and-drogue system. Boeing only delivered a 767-CTA to Italy so far.
http://cencio4.wordpress.com/2008/07/02/the-boeing-767-delivered-to-the-italian-air-force/
The lease deal probably would have been more profitable to Boeing had it run over the life of the system but I doubt that was ever the plan. the UK leased a handful of C-17s and soon (as funds became available) turned that into a buy, and I think added aircraft to it. That would have taken place with US tankers as well.
The RAF lease deal was for 7 years. UK decided to buy one C-17 and 4 leased C-17 at the end of the current contract. The US lease deal was differently with a longer duration and worse conditions.
About one thing I'm wondering. The idea was to use an existing aircraft as base for the new tanker. EADS offered one while Boeing offered a non existing version of 767.
As to the period and conditions of a lease; I think the whole concept was that the lease would never go to term, that a purchase would replace it at first opportunity.
Prices and terms I know nothing about but I have seen USG 'negotiators' lock tight at the mere mention of 'profit', I've heard them swear they were being cheated when a truck load of audit information said otherwise, and I know they stiff the donatons jar when the doughnuts are brought around.