I see this is an older thread but I saw this would like to chime in.....
I asked about this on the Predators board some time ago and got a very heavy "No!" for reasons that
@Soundgarden mentioned.
However I'll add this. I've been to Memphis a few times, one of the things I noticed while there is the sports relationship between Memphis and Nashville is a lot like Charlotte and Raleigh, lot of pettiness between the fans/writers but this one has a bit of a twist. There are a lot of Cowboys fans in Memphis and very few Titans fans, this goes back to when Nashville received the Oilers when Memphis was vying for an expansion team in the 90's, as well as the Oilers unsuccessful temporary stint in Memphis that saw them leave for Vanderbilts stadium one year before Nissan Stadium would be completed. Memphians still hold this grudge.
That, and I've got family in Memphis who have lived there for 25 years now. They had no clue that the RiverKings existed. Some of that may have been because the team played in Southaven, MS but they looked at me funny when I told them this. To put it bluntly, I don't think Memphians would support a Predators-AHL team for the reasons stated above but also because there's very little interest in Hockey. It's a Football town and everything else is an afterthought.