rhgb should be installed by default but I'm not sure. try this ( I am at work at a windows box
if it IS there you can add it to your grub.conf
so last part of kernel line would look like
ro root=/dev/sdaX rhgb quiet
if it is not there you can check its dependancies with
or you can
and look at what all it wants to install before okaying it
just to clarify though you are not wanting a grub splash right? You mean splash for after the grub loader?