I see this is an old thread, but being a Trekkie I couldn't let it die just yet--
Two points-- (1) Ferrous sulfate is a common flocculant used in water treatment. So if you're going for an opaque, blood-like drink the iron pills are going to work against you, aside from the toxicity questions. On the other hand, the fact that they generate floc might help keep the concentration from getting too high, in that the iron would settle out with the yeast.
(2) On Star Trek, the Next Generation, Guinan turns Worf on to prune juice, which he dubs "a warrior's drink" and proceeds to consume every time he can sneak off to the bar. So if the blood ale doesn't work out maybe a prune beer would suffice?