<a href="http://www.cudatel.com/products/index.php#models.html">Barracuda Networks CudaTel Communication Server - Products</a>.

Interesting but kind of pricey and a proprietary management interface.  I couldn't find any documentation on their web site -- well if it's there it isn't that obvious.  Phones look like they're locked into that platform as well.

Next: Check out price of generic rack mounted PC hardware.