|laziness, impatience, and hubris|
There was a recent question on comp.lang.perl.modules (I think) regarding a perl module that wraps ALSA. Lack of response would indicate that such a beast does not exist.
Last time I checked, the GSL modules had not been updated in quite some time - so it's likely they're up for grabs. And I know that Neil Watkiss is prepared to farm out Inline::CPP (and possibly other of his modules - see http://search.cpan.org/~neilw/).
Then, on the PDL mailing list there was some talk of wrapping s2plot (http://astronomy.swin.edu.au/s2plot/).
These are just what comes to mind off the top of my head. I'm sure there are many others. It's really just a matter of finding something that interests you.