Problem with wetsuits is that nobody makes kayaker's wetsuit
for artic waters. Myself have designed one such and it works
also when diving (under ice). Here are some specs:

Two-piece 6 millimeter rubbercoated suit:

- Pants are designed for sitting position, with a zipper which
reaches down to the asshole. Zipper is waterproof and opens from both
ends. You can comfortably sleep in the suit, because them itchy
sweating private parts can be easily vented.

- Top piece looks like any other diving suit top, except to avoid
chafing, there is ample room at shoulder and armpits. Marked
difference is at elbows, the are cut for 90 degrees angle. Also there
is ample room for extra warming layer, typically a sweater of some
fancy fleece-like material.

Here are some pictures of the basic design, somewhat wornout after
exhaustive testing among floating ice on the Baltic:
http://www.kolumbus.fi/timo.noko/puku/

The actual suit is four-piece, because the wind is much colder the
the water. Hence I have also designed heavy-duty nylon long-john and
jacket which have same dimensions and functions as one above. They also
protect the wetsuit proper because the rubbercoating is less durable
than nylon coated. Rubbercoating is however much more flexible and
necessary when using 6 millimeter material.