I gave 7c6b964 a spin but I'm not sure it's working as intended. I created a new StatusBar, avoided calling SetStatusBarColor, but the bar always comes out as white.

Calling GetStatusBarColor() returns 0.999..., 0.999..., 0.999..., 0.999... - it looks like you'll never get in to call SetStatusBarColor()

Also, how come you decided to go with hard coding the colour values over using GetItemQualityColor(6)?

The hard coded value is what Blizzard uses