Well, I am not too sure what all is involved with making Kosher products, but there are plenty of cuts on the forward half of the beef that can be used for sausage. Not only that, but one can get synthetic casings made of cellulose or collagen and avoid any problem there (pork casings are out).
I guess that one can always make all beef summersausage or add some lamb or mutton. There are Kosher salamis and hot-dog recipes, to name a couple. You can always cure and smoke fish and use it like Herring or Whitefish, or even Lox. Rytek Kutas' book, available from
www.sausagemaker.com is a good book. Ask your own butcher for recommendations.
Most sausages will contain a fair amount of fat--say 25% or more, sometimes. It is needed for good taste and texture, but there are restrictions on fat content for Kosher meats.
If you don't really need it to be Kosher for Passover, or super Kosher, there might be an everyday standard that you can live with. That is outside my area of knowledge.
There are synthetic fat replacers to help your sausage.