"you can see there that the banding patterns are all pretty much the same."
Must i point out that seemingly small differences in DNA arrangements constitute vast differences in products from that code of DNA? Even tho these chromosomes to the eye look similar and seem to have but very small variations on a genetic level those can be incredibly vast differences. So show me a genetic "map" of all those "small" differences in the species and if the genetic "map" shows them to be small differences then i concede to ypur point. Til then dont trust your eye to make decisions with DNA;)