I know I can change PowerShell console colors by setting in my profile something like:
$Host.UI.RawUI.BackgroundColor = \"White\" Clear-Host
I doubt that's possible. The $Host.UI.RawUI.BackgroundColour is a System.ConsoleColor enumerator, thus there's only a finite set of colours that you could select. http://msdn.microsoft.com/en-GB/library/system.consolecolor.aspx