After reading Todd Anglin's blog post
about optimization using HTTP compression, I googled around. There are some solutions available, but some of them are also doing what RadScriptManager and RadStyleSheetManager already do (combining scripts/stylesheets in one compressed file), so I am not sure if there is a benefit of using those solutions doing double compressions of script and css files. Others seem to have issues with handling AJAX callbacks properly.
So it would be great if you could make a kind of RadHttpCompressionManager to complement the two other managers ensuring that the compressed output is compatible with your controls - this would be a perfect addition improving your excellent suite of controls.