For a small restaurant the Lyons' Den has some reasonable choices once you get past the Bud dishwater products.
http://mysite.verizon.net/vze3nm2c/lyonsden/id9.html
The don't list Guinness but there sure is a tap in the photo.
While the Woodstock Inn Brewery has only their own on tap, there are many interesting choices.
http://www.woodstockinnbrewery.com/home.php