I'm sorry to hear about your problem with the broken Link piano plate.
I have a Link E, serial no. 3448, so I know the plate style.  Here are
a couple of thoughts which may help you find a solution.

There is an excellent article on piano plates and repairs on the Piano
Technicians web site under Sample Journal Articles November 2000 at
http://www.ptg.org/journal-sampleArticles.php

 [ http://www.ptg.org/ptj/plate_issue.pdf  (6 Mb)]

The file takes awhile to download, but has a wealth of information.
Rob Goodale summarized some of the methods in his last post.

Re-casting the entire plate, although possible, is for the most part
not practical.  If you use the original plate as a pattern, with a
shrink rate for cast iron of approximately 1/8" per linear foot, your
new casting will be about 3/4" too small in width.  That's before
casting clean-up and this does not address any distortion that may be
in the old casting.

The cost to have a real foundry pattern made, along with the associated
core boxes, etc. is quite expensive and can easily exceed the value of
the piano.  At present there is only one foundry in the USA that
regularly casts piano plates and they are very independent.

It seems that finding a like piano plate may be the best solution at
this point.  Junker coin pianos with good plates do turn up from time
to time -- the trick is to find the right one.  Fortunately, the same
plate seems to have been used in a number of earlier Seeburgs with
Haddorff-supplied pianos, along with other coin piano makes.  Since it
is only a partial plate there is no name in the casting to contend
with.  I have an orphan Marquette player piano plate similar to your
Link, but the scale may be different.  I'll check.

Piano plates seldom break without cause and will withstand a fair
amount of abuse before breaking.  As was noted in an earlier posting,
determining the cause of failure is very important and the necessary
repairs made or you may be back at square one.

Dana Johnson
Johnson Restoration & Supply

 [ Not too long ago an experienced piano tech told me of a similar
 [ situation involving (I think) a Seeburg.  He said if he were to
 [ do the job he would remove the keybed and the case walls and then
 [ replace the entire "strung back" with a similar piano from the
 [ same builder, like Haddorff or Seybold.  -- Robbie