Have you had a look at the marvellous File::Find::Rule which makes recursive file searching ever so trivial? To demonstrate I shall take your example snippet and map it to a File::Find::Rule command

## UNTESTED ##
use File::Find::Rule;

my $dest = shift;
# just needs case-insensitivity ...
my $rule  = File::Find::Rule->new();
my @files = $rule->file()
                 ->not( $rule->new->(name => '*.obj') )
                 ->exec( \&foo )
                 ->in( $dest );
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So if you do go ahead with the module File::Find::Rule should fit in nicely.
HTH

_________
broquaint