Attention Denon 5700 owners

I have questions and was hoping some of my fellow 5700 owners have boldly gone where I havent yet.I am curious as to what it actually takes to get the 5700 to 6.1 channel or 7.1 channel status? It says in the manual about the 6-8 channel inputs for future formats.I was wandering if I could find a dvd player with 7.1 decoding and additional amplification for the extra channels if that would work as good in reality as it sounds in theory.Any of you guys attempted this? I am really not sure about this so any and all input greatly appreciated.The 6.1 and 7.1 formats arent worth the cost of another reciever but if its practical I would like to take a stab at it.I have only seen one dvd player with 8 channel decoding,I am sure that there are more than just one,so dont be afraid to list any and all dvd players you know of,that have 6.1,7.1 channel decoding.
Thanks in advance
I am not 100% sure but I belive that this is somehting that will need an aditional component in order to support more than 5.1. I have the 5700 and am considdering upgrading to the 5803 for the analog to digital video "up-conversion". Do you have any idea what the 5700 would be worth?
probably not much,anything less than 7.1 seems to hold its value about as well as computers.I saw one listed somewhere not to long ago for $1000 but I am not sure if it sold or not.