Try this site, they have parts made by the original vendors. They have the Pantera rack for (not cheap) 360 Euro.
http://www.autoepoca.it/?s=de+tomaso
PANTERA INTERNATIONAL
A DE TOMASO CAR CLUB
Presents the De Tomaso Forums
The On-Line Meeting Place for De Tomaso Owners and Enthusiasts From Around the World
Clicking on the banner will take you to the sponsor's website.