If you are using a Matrox MXO2 in the setup, I'm guessing you are recording directly to a computer? You should be able to feed a component video signal plus audio directly from your Matrox to a standard DVD recorder and record real time. You should also be able to connect the EX3 directly to a standalone DVD recorder such as the one below which handles dual layer DVDs but only has a composite connection. You can feed a DV signal to the recorder at the same time you are recording to the camera cards.
http://www.bhphotovideo.com/c/product/631186-REG/Sony_VRDMC6_DVDirect_MC6_M...
Dave
David Wheeler
EX1R; EX3; FCP 7; 17" MBP, MacPro Quad, Matrox MSO2,CS5
dave@marcombiz.com