Re: the 1.4x TC... what about a 3rd party option, such as the one from Kenko everyone seems to like?
Re: airlines... there was a recent discussion about this in the Canon forum and it seems a photo vest is a good option for bringing extra gear on the plane, then repacking the bag at your seat.
BTW, I don't think your kit is excessive. For years my typical travel set has been 2x 1D series (because this was all I owned), 16-35, 70-200/4 IS, 50L, 85L, 1.4x and another 'bonus' lens, such as 17 TS-E, plus flash and requisite accessories... and this all fit in a 21L backpack, though weighed between 11-13kg...
I'm of the opinion of 'why have great equipment if you're not going to use it?'
Congratulations! It sounds like a both a fantastic reason to travel and a wonderful trip.
And now I'm going to try and make you rethink the tele. Consider this- it would be very easy to make your 135 into a 270. You've got 21MP to play with. I know it's not the same, but unless you plan to print large, 10MP is plenty for the web and a photo book. Your 35 T/S does something no other lens you own can do, and it's well suited for architecture and panos. If I were going to visit places where I knew I could make good use of that lens, it's the one I'd want with me.
Just back at home in the last half-hour after many enjoyable weeks away.
I can'y say I regretted carrying any of the lenses I carried, even though the 70-300 had minimal use, it was valued for those few occasions. The FD 35 T/S would undoubtedly have been useful, however I simply had to make a choice between that and the 70-300; moreover I think that the T/S levers would have made the lens too bulky to fit into my available space.
The M8 and CV 35/1.4 got quite a bit of use and I also used a Jupiter 50/1.7 a number of times.
I will post some shots in due course; right now jetlag is taking its toll.
As a final sentence I would add that Iceland and its people are marvellous and we intend to return someday...
