Since you are in the Philly area you can try: Just to name a few in the area

- Wee House of Supplies in Chalfont, PA
Call Angus at 215-343-0337

- USA kilts has ghilles on their site

- Donegal Square in Bethlehem, PA
www.donegal.com

- Highland Heritage in Willmington, DE
http://www.highlandheritage.com