Hi Dave,
In answer to your questions:
I've never used the Backcountry access or Trekkers before but would imagine that the alpine bindings AND them would make for a pretty heavy but will defer to others who are familiar with them before speculation - anyone with better beta?
As for construction, I'd ask the ski techs about the different models if that info's not on the ski itself or easily-available documents on the ski.
Ask some of the patrol guys about the pro deals.
Dynafit-compatible means that the AT boots have notches in the toe which fit a super-lightweight binding that has small pincers that grasp the boot's toe rather than a standard type toe binding that comes up over a DIN-type ski boot toe.
http://www.backcountry.com/store/LIF...ml?id=d8ARDKD4
As for the lug sole (and walking adjustment), its 'cause these boots are made for walking and that's what they're going to do! There are plenty of times when you'll hike for awhile before putting the skis on the snow to start skinning, also you may find yourself kicking steps into a steep face or traversing hard snow where an alpine boot may not grip as well as you'd like.
Give me a call and we can talk about it more.
--Andy
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