The Pegasos Openfirmware has it's own language (Forth) in which you can even write scripts if you like. (You can make it autoboot, or boot different OSes when holding down a key, etc.)
Never the less, Openfirmware is text based (which is a butt ugly thing compared to what Amigas offered) but one can get used to it. Hope soon there will be more advanced, non text based bootmanagers.
There may be already other possibilities, my knowledge is quite limited though.
