I was searching through pubmed and actually found one meta review...

Rev Psiquiatr Salud Ment. 2011 Jul;4(3):126-43. doi: 10.1016/j.rpsm.2011.02.005. Epub 2011 Jun 14.
Efficacy of second-generation-antipsychotics in the treatment of negative symptoms of schizophrenia: A meta-analysis of randomized clinical trials.
Darbà J1, Minoves A, Rojo E, Jimenez F, Rejas J.

Abstract:

OBJECTIVES:
To determine whether second-generation-antipsychotics (SGAs) are effective for negative symptoms treatment in schizophrenia.

METHODS:
Two meta-analyses were carried out using placebo or haloperidol as comparators. The search included the following databases: Pubmed, The Cochrane Central Register of Controlled Trials, Proquest Health and Medical Complete, Science Citation Index Expanded, and Current Contents Connect. The outcome measure used was the change in negative symptoms, choosing a standardized statistic (Cohen's d) to synthesize the data.

RESULTS:
In the placebo-controlled meta-analysis, the effect sizes (Cohen's d) obtained for amisulpride, haloperidol, olanzapine, quetiapine, risperidone and ziprasidone were 0.52, 0.34, 0.43, 0.36, 0.40 and 0.46, respectively, favoring active treatment against placebo (P<0.001 in all cases). The haloperidol-controlled meta-analysis only showed a statistically significant trend favoring antipsychotics over haloperidol (Cohen's d=0.15).

CONCLUSIONS:
Most antipsychotics (amisulpride, haloperidol, olanzapine, quetiapine, risperidone and ziprasidone) are effective in the treatment of negative symptoms. Amisulpride and ziprasidone showed higher effect sizes.


Update: I think it is important to point out that this study was funded by Pfizer, the makers of ziprasidone (geodon). It's disheartening to know that the only reason amisulpride isn't approved for use in the US is simply due to it's expired patent status.