[Rodney]

EIN or TIN - Which do wholesalers prefer / require? Any disadvantages to getting an EIN?

Most wholesalers ask for a TaxID number, however I think an EIN number will work just as well.

What is the NAICS code for clothing? This is required for an EIN application

I searched google for NAICS t-shirts and I found this page that should help you:
http://epic.od.nih.gov/naics/code_index.asp?search_letter=T