Just for my sadistic amusement, behold the glow tag.
Now you too can make the world a glowing place
This allows an interim solution for people wanting to see how various effects will appear when combined in the donor shop, just create a test message and try it out.
Also, this will annoy the crap out of many users. bonus points!
But because I am a benevolent sadistic dictator I've also made the "Remove User Font Modifications" option now suppress bg, highlight and glow as well within posts, giving you unprecedented degrees of boringness potential for your viewing pleasure.