Okay, it just occured to me that the docs for skin text source was left out. Anyways, here are some of them:
"DVDTitle"
"C_Free"
"C_Total"
"E_Free"
"E_Total"
"F_Free"
"F_Total"
"G_Free"
"G_Total"
"C_FreeMB"
"C_TotalMB"
"E_FreeMB"
"E_TotalMB"
"F_FreeMB"
"F_TotalMB"
"G_FreeMB"
"G_TotalMB"
"Time"
"Date"
"DateTime"
"NickName"
"CPUTemp"
"MBTemp"
"CPUTempC"
"MBTempC"
"CPUTempF"
"MBTempF"
"SongName"
"SoundTrack"
"SongTime"
"Tray"
"DVDType"
"VideoMode"
"IP"
"Subnet"
"Gateway"
"DNS1"
"DNS2"
"AppVersion"
"MAC"
"Version"
"HDDKey"
"SerialNum"
"NumClient" -Number of FTP client currently connected
"ChipID"
"Newsfeed"
"LaunchMode"
"FanSpeed"
"Thread" -Number of worker thread currently running
I have a few more like, number of uploaded/downloaded files, number of failed uploaded/downloaded files, bytes sent and received...among other things.