CNewton;
depending on how many upconverters you need, you may want to save some money by getting only one and make it as a source on your router.
Miranda works great, the problem with that is the setup is kind a problematic, because you need to navegate throguh a sets of switches in the front of the card, plus the fact that if you need downmix your audio, that's an option ( another 2 to 3 grand), I have thre or four and Icontrol ( another option) that allows me to change settings using an ethernet conenection.
I will go with a stand alone unit, as I mentioned before.
good luck
JP