I have a logitech 325 (the perfect inexpensive wireless mouse for people with small hands) that I inherited from a former labmate in my post-doc lab with an awesome design on it that involves birds and branches. Unfortunately logitech opted for light blue for the grippy parts and over the years it has become pretty gross and discolored where my fingers grip (and the scroll wheel).
I have inadvertently acquired two more of this model, one with a purple floral pattern that is very meh and a plain red with black grips (where I don't have the original receiver). And I just discovered that it's possible to swap the covers!??! I might be able to put my cool birds cover on the black base! Won't look quite as matched as with the current white edges, but still!
I'd also have to figure out how to change the receiver over to a different mouse, but that's theoretically possible...