Thanks for all the replies...
As far as the condo board and regulations go - yes, I need approval
from the association, and I'll file a "variance" request outlining the
work, etc. However, I don't see a real problem here; I expect it will
be approved. I could be wrong, but I know the association fairly well
(people and rules), and I would be surprised if the request(s) were
rejected. There's nothing in the bylaws that explicitly prohibit the
work I'm looking to do (provided I get the variance approvals). I
will submit all the project request(s) at one time, though - that way,
I don't get working into my project plan only to find out along the
way that one part of it is not going to be permitted.
I appreciate the comments about payback - strictly speaking, this
project would be a "loser" financially. However, when I asked whether
such an endeavor was "worth it", I wasn't thinking in financial terms;
rather, I am interested in the amount of effort vs. comfort level (and
maintenance) of living in the unit.
It is nice to see that I'm not the only one who has faced this
situation. I'm going to look at using the rigid insulation board, as
well as talking to two contractors I know about building the walls
"in" (reducing the living area by a bit).
The possibility of having to use custom jambs is not exciting to me -
but, I'm redoing the doors and windows anyway, so if I must fashion
custom openings/jambs, it'll be done.
Regarding the "shared walls" - they're block walls with drywall glued
to them. They don't seem to be significant in the energy/comfort
problem at the moment, but I figure I can always build them in, too,
if necessary. I guess I'll want to determine whether I want to do
this before I finish the interior, though; this one remodeling
(rebuilding?) project is enough!
Thanks again for the feedback.