The food in your first link, for which a b'racha isn't said, is food that was stolen. I don't think we can generalize from that to all forbidden foods.
The Rambam says that any food that is asur does not get a b'racha either before or after. However, the Shulcan Aruch says that there is at least one case where you do say b'rachot afterwards. This answer to a question about making kiddush on Yom Kippur says:
The Shulchan Aruch (618:10), however, writes that mention of Yom Kippur should be made in bentching (i.e. say Yaaleh Veyavo) with the reasoning that because one would be bentching anyway and the same paragraph is said in the prayer.
(SA reference verified by Scimonster -- thanks.)
For those who pasken based on the Rambam, the answer seems to be a clear "no". For those who pasken based on Shulchan Aruch, I make the following argument:
If one is expected to bentch after eating on Yom Kippur -- which he would only do if there were a pikuach nefesh reason to be eating -- then it seems reasonable that he would also say the b'racha beforehand. (Are there any cases where you bentch but don't say the earlier b'racha, after all?)
If this reasoning applies to forbidden eating on Yom Kippur, then it seems to me that it should also apply to forbidden eating at other times. It is possible that there is still an exception for stolen food per Sanhedrin 6b (which says you don't make a b'racha); that case would need to be checked for post-talmudic rulings. But for food forbidden for other reasons (e.g. kashrut issues), this reasoning seems to apply.