I just recently restored a 2004 Genesis Silver B for my father in law and wanted the same thing. Noticed the new Spirits had the raised warming rack and like it a lot better.
It's not "made" for the Genesis, but works great because the cook box is exactly the same for the old 3 burner Genesis and 3 burner Spirit, even though they're now made in China. The notches are in the same spot and it fits right in. According to the schematic, it's part 91289.
I ordered it along with a few more parts for the Genesis, and they didn't give me any trouble for it not being the right grill. They just said they weren't sure it would fit, but I told them I measured it at Ace and the cook boxes were exactly the same dimensions. I think it was about $17 + $7 to ship. Keep in mind they ship everything for a flat $7, so if you need some more parts it's still just $7 to ship.
Good Luck!