Recently someone asked for help with NYC death record and naturalization record offering to pay for costs etc. It would have been easier to send directly to the Municipal Archives and to the National Archives branch for the documents. Deaths before 1949 are available at Municipal Archives for a fee of only $5.00 and don't take months (actually Dept. of Health is now doing better with average wait under 5-6 weeks).
Check the JGS book on Genealogical Research in New York Metropolitan Area for details and keep up to date with movement of records by reading Dorot (JGS NY newsletter). Or look at syllabus >from conference in 1999 for updated information.