Pretty much useless, but fun.
have your macro ready in character specific macros. open my computer, got though and find: program files/world of warcraft/WTF/Acount/[youraccountname]/[yourserver]/[yourcharactername] now open macros-cache in notepad, find the macro you want to have no icon for example
now the Spell_Magic_FeatherFall is the icon name. just change it to "-" or "none" doesnt really matter as long as its not the name of an icon when you log back in it shoulde be blank with the name of it on nothingMACRO 1 "logout" Spell_Magic_FeatherFall
/Script Logout()
END
notice: if you change the page or switch around the icon it shows it as the icon that was in that place, simply logout and back in it should be blank again
Edit: this also works for non-char specific macros. stop at the account folder and open macro-chache there, and it should work the same