Many shuls read zachor a second time on Shabbos Zachor, either before or after mincha, to allow people who missed the first reading to hear it. In all the cases I've heard, this is without a bracha.
Another procedure would be plausible to me, but I've never heard of anyone doing it. Why not do it as part of the normal Mincha reading? Take out two Sifrei Torah, merge two of the normal Mincha aliyot into one, and for the third aliyah read Zachor. This would have the advantage of saying brachot before and after reading Zachor.
Are there any places that do this? What are the objections to reading in this way?