In reply to JdotP:
Would you even attempt Mt Blanc in December in Nepal Cubes ? and given that the Caucasus will probably be higher and colder.....
If you dont want to buy Spantiks or a similar boot you could always pick up a cheap second hand pair of Vegas or, if you really do for some reason decide to go single boot then forget the Yetis and at least go warmer and get insulation underneath the boot where its in contact with the cold
http://www.needlesports.com/40/products/forty-below-k2-overboot.aspx
(but you could buy some Vegas for that price and still have change) or you could buy Spantiks and sell them on afterwards It all depends whether you have ambitions for future colder, harder, higher routes.
You can always buy new replacement boots you cant buy replacement toes
Post edited at 15:30