Are there any bindings available to fit plastic double boots on nordic skis
(for approaches to climbs), rather than having to carry climbing boots and
wear cross country boots?

Some winter hikers I knew in New England swore by the Scarpa T2s & T3s
-- i.e. a ski boot that's also suitable for mountaineering. There's a
dated but relevant thread he

http://www.greenspun.com/bboard/q-an...?msg_id=0001PY

you could also post on rec.skiing.backcountry