I have a Nitrogen Cylinder for sale on eBay that includes a CO2 gauge adapter that allows you to dispense beer with Nitrogen or Beer Gas without having to buy a separate Nitrogen gauge.
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=271088069489
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=271088069489