Difficult matrix

[Tobias Burnus <burnus@gmx.de>]

Hi,

has anybody an idea or tip how to typeset the following matrix?

   /  L  ||  0   | 0 \  r'
  | =====||::::::|::::|::
  |   0  |:  A'' | 0  | r
  | _____|:______|....|..
   \  0  ::  0   : 0 /  m
       r'::     r:   n

L, A'' and 0 should be `normal-sized', whereas r', r, m and n are
smaller (scriptsize).
The L is surounded (bottom + right) by a double line, which then becomes
a doted or
a dashed double line which exceeds the length of the parentheses. Bottom
aligned
on the double dashed/dotted line is the Dimension r' (scripsize), bottom
aligned.
Next row: A single line stretches from the left 0 over the ), this line
becomes
dashed/dotted after it crosses the solid line right of the A''. etc.
The r', r and n on the bottom are right-aligned and also scriptsized.

Tobias