I've yet to hear of "Southern Metal" as a subgenre. There are some Southern Rock bands who sometimes take a bit of a Black Sabbath-inspired touch and straddle the line between Southern Rock and Doom Metal - bands such as Goatsnake, Iron Hearse, and, to some extent, Corrosion of Conformity. As for how you want to name your band, whatever appeals to you. There really isn't a set definition for how to name a Metal band, although perhaps there are some guidelines you'd want to stay in between... you wouldn't want a name which would lead people to think you were a Black Metal band from Norway.
as wikipidia states Showdown is a 'Christian southern metal band'
There are three Metal bands by that name - a Power Metal band from the Netherlands, a straightforward Heavy Metal band from the United States, and a gothic/symphonic band from Indonesia.
metal is that part.
no.
La phaze
There is a band named suburban tribe that is a metal band from Finland but on March 2011 the band has decided to disband.
Band Name: After Me, The Flood Song Name: Speculations/Phobias
Sugar kisses
Paracoccidioidomicosisproctitissarcomucosis, a Mexican goregrind band, but only if you consider that form of music as metal (personally I don't think it's 'real metal' but that's another debate for another time).
Egypt Central is the name of an alternative metal band which, contrary to the band's name, was established in Memphis, Tennessee. Much of the band's music can be heard on YouTube.
One can find some ingenious band names online on websites, such as Ultimate Metal, Band Name Maker and New Band Name. It is important to choose an original band name.
Wicked Wisdom