After some coersion, your response led me down the proper path. Here's my updated code snippet:

my $match = pack 'H*',
            '53005f00560045005200530049004f004e005f004' .
            '9004e0046004f0000000000bd04effe00000100';
open(FILE,$file) or die $!;
while (<FILE>) {
  if (/$match(\S{2})(\S{2})(\S{2})(\S{2})/) {
    print "Found match!";
    print join('.',map {unpack 'H*',$_; } ($1,$2,$3,$4);
  }
}
close(FILE);
[download]

I think my confusion rested in how perl would handle a binary file. Seems that the DWIM held true... I was making it harder than it was.

Thanks for your help!

Cheers,
Shendal