We may see some 7.1 source material start to emerge from HD-DVD / BD-DVD. For all the other source material available, you may want to try using DPLIIx / Logic 7 processing to generate 7.1 distinct outputs for 2.0, 5.1, (and perhaps 6.1) input sources. That would make the unit a 7.1 PrePro rather than a 7.1 preamp.
As I inderstand the way they work, DPLIIx / Logic 7 extracts and redistributes the surround information from the source, they don't add anything.
I've been listening in 7.1 for many years, and find it has much better surround envelopment than 5.1.
Bruce