I have Mac pro with dual monitors (both video outputs are busy). Any idea how to connect SD TV to monitor PP output as it would be seen by client (TV studio)?

Intensity Pro card works and is relatively cheap: Blackmagic Design: Intensity (http://www.blackmagic-design.com/products/intensity/)

I originally got it for HD monitoring but wasn't thrilled (limited on what formats it supports), but now use it component out to an old Sony broadcast monitor for SD edits. And I use it for audio to feed my monitors (just RCA, but works well).

Matrox MXO
Matrox MXO - Overview (http://www.matrox.com/video/en/products/mxo/)
It can be used to calibrate a monitor that otherwise couldn't be for HD monitoring, like an HDTV for example.

My problem is that after PP in HD I need to down convert it to SD and monitor on SD TV to confirm expected quality. I have no idea how to hook up SD TV to my PP system.