In McCollum v. State of California, 2009 U.S. Dist. LEXIS 11154 (ND CA, Feb. 13, 2009), a California federal district court held that a volunteer Wiccan prison chaplain lacks both traditional standing and taxpayer standing to bring an Establishment Clause challenge to the California prison system's policy of providing paid chaplains for only five faiths-- Protestant, Catholic, Jewish, Muslim, and Native American. As to traditional standing, plaintiff is attempting to assert rights of third parties, i.e. Wiccan inmates. As to taxpayer standing, plaintiff is not seeking to stop the expenditure of state funds, but rather to increase or transfer expenditures to have Wiccan chaplains hired as well. Establishment Clause taxpayer standing extends only to cases where a taxpayer is attempting to lessen expenditures.
UPDATE: As pointed out by a commenter, plaintiff also claimed standing on the basis that creation of a paid Wiccan chaplain position would give him an opportunity to be hired-- something he had been told he was ineligible for currently. The court said that it was speculative whether, even if (as requested) faith-neutral criteria were applied, he would be hired since that depended on needs of Wiccan inmates.
UPDATE: While the Northern District of California denied standing to a chaplain to challenge the 5 Faiths Policy, a decision from last year has just become available through LEXIS in which the Eastern District of California finds that an inmate does have standing to challenge the policy. In Rouser v. White, 2008 U.S. Dist. LEXIS 107199 (ED CA, Sept. 16, 2008), the court also found that plaintiff's complaint alleges "plausible grounds" for relief in his Establishment Clause challenge.