As you mention they're not just offset differently, they're also at different resolutions. In theory you can achieve something similar by rendering at a higher

As you mention they're not just offset differently, they're also at different resolutions. In theory you can achieve something similar by rendering at a higher resolution and downsampling with an appropriate filter, but then you're using a completely different algorithm that has nothing to do with the RGB "subpixel" cleartype rendering anymore.