A possible source within the US would be e.g. GREENLEE TEXTRON (US# 1-800-435-0786, greenlee.textron.com) Various rack equipment manufactures and also most Neutrik distributors do offer as well panels with D size cutouts.
USD: 25,700VND
- Head Office: 396 -396A Le Van Luong str. Tan Hung Ward, Dist 7. Ho Chi Minh City. Viet Nam