It's been a long time, and i hope you figured this out. But nevertheless, i was reading the 1993 Issue 14 of Video Toaster User, and they had an article titled "Toaster goes international". There's been mention of the Prime Image TBC, with very good results!
Here's a bit of the text:
At the Montreux exhibit, Prime Image demonstrated its Stnd/Con TBC in a Toaster System. Two standards converting TBCs were used on two video input channels to convert a PAL signal to NTSC so that they could be
processed by the Toaster. A thlrd standards converting tbc was used at the Toaster's output to convert back to PAL.
Response was so encouraging that KeIper International, a New York-based international equipment distributor, plans to build 1,000 Toaster 4000 systems that use a minimum of three Prime Image Std/Con TBCs for sale in Europe, South America, and the Pacific Rim.
Although this example shows the use of three (3) tbc's, it proves that it has been done. However, acquiring such gear would be a miraculous task...
