Mark,

With all due respect:  stop faffing about and get down to business.
You received some good advice (which snowballed into something else),
and have elected to continue talking to mechanics who are neither
interested in nor professionally geared towards this type of repair.
I spent over a decade professionally in automotive and heavy equipment
repair -- all in the rust belt with a heavy lean towards fabrication
and "making the job go".  One of your mechanics suggested a welding/
fabrication shop (albeit with an out of the blue "estimate"), as did
I.  You may indeed have to separate the frame a bit for sufficient
access, but we're not talking about rocket science or necessarily
complete separation.

Find a welding shop willing to do the repair -- i.e. one with plow
frames, construction equipment, and the sort piled outside, not a
boutique in the suburbs.  Show up ready and willing to get the job
done, asking what you need (as opposed to what you want) to have
repaired and the non-restoration circumstances surrounding it.  You
can't get a serious estimate on this type of job if you waffle about.
Bring some graphic documentation about the specialty repair items in
the aftermarket....see links below.  I think the "frame repair" piece
might solve a lot of your concerns, probably not worth purchasing to a
well equipped shop, but it might be the bit of encouragement they need
to jump in.

I don't mean to be too abrupt but this forum is only good for talking
about doing work, not getting it accomplished.  No one can assess your
damage or risk factor without at the very least seeing what you're
talking about (a few photos, perhaps?)....I don't know what you
expect.

http://www.grandwagoneers.com/stainless_straps.html

http://www.grandwagoneers.com/frame_repair.html

http://www.grandwagoneers.com/oem_skid_plate.html

I'll be happy to respond to some pics, as will others, and we look
forward to hearing about how the job progresses.

Jon