Bonnie, I have a vague recollection from my researching recipes some time ago that one did suggest doing just that, using a pan instead of casings. I often make liver pate in canning jars - cook in a water bath in the oven without the lid, and then put on the lid before freezing the extra (my recipe makes 4 or 5 of the jars that I use). I should think that blood sausage would work just as well.
I have found a number of European recipes (well, Swedish from dietdoctor, and German from various sites) that use psyllium husk powder as a binder/thickener. It has no taste of it's own, and works very well. I use it in meatballs and the like, as well as certain baked goods. Don't have the recipe right at hand, but I believe I put some in the liver pate as well.

ETA: Just looked up Polish kiszka; looks good