Stealth Lobbyist Disclosure Act of 2005 - Amends the Lobbying Disclosure Act of 1995 to redefine the term "client" with respect to coalitions and associations on whose behalf a lobbyist must file a registration. Provides that, in the case of a coalition or association that employs or retains other persons to conduct lobbying activities, each of the individual members of the coalition or association, and not the coalition or association itself as under current law, is the client for whom a registration must be filed. Makes an exception for certain tax-exempt associations and for certain members of a coalition or association if the amount reasonably expected to be contributed by such member toward specific legislation-influencing activities of the coalition or association is less than $1,000 per any semiannual period.