This group does not seem to use distiller's grains as a carrier but Dr. Kellon mentioned them (maybe in NCRplus 2011 course or EC horsekeeping).  I have been using them for a couple of years before Cory tested positive for IR.  I recently tested two batches and they are under 6% ESC + starch.  It smells like fresh baked bread and I can feed minerals as well as bute or other noxious meds in one cup (~ 150 grams).  My local feed mill carries it.  No soaking required, all I do is take a thermos of warm water up to the horse shed to mix everything together and eliminate dust.