Once an ability of a permanent you control has triggered, making it colorless won't cause that ability to trigger an additional time
So why havent I broken down and built a Sliver deck before
Is Grma, Saruman's Footman legal to play
Not just because of the archetypal significance, but because casting this for double blue or double white in any other color combination sounds completely untenable
It pulls back what you want, and can dodge interaction by activating a second or even third time
It had some minor other notes to play, such as being part of the theoretical Extended Yawgmoth's Bargain deck I was asked to build to show how often it could kill on turn one, and providing the method of execution in some other cases, but Cadaverous Bloom is all about the Prosperous Bloom deck