But I don’t think it is neccesary for using float textures on ATI hardware. AFAIK this limitation only originates from GFFX-class hardware, on ATI and GF6800 you can use float textures on any target…
GL_TEXTURE_RECTANGLE_EXT, it carries the same enumeration than the ARB counter part.
I tried using it on my work machine but it doesn’t seem to work quite well