RE: 120VAC to 12VDC converter???
Do a google search on pyramid power supply and look for someone that has the 14 amp one (or less, I like bigger so less load or have 3 chargers running on it!) for around 40ish bucks and be done with it. Excellent quality, quiet and you don't have to do anything yourself like the PC power supply mods...
Radio Shack even has a 12V power supply, I think a small 4 amp one and a larger 10ampish one.. they're more expensive than the pyramid though.