it's rather unfortunate that,Douglas is no more.anyway,if Douglas named the device after the living creature 'mouse',he never gave a plural form of the device and so it'll remain that way.the only mention name that i'll go by is 'mouse devices' as the plural of the computer mouse.i think it's a matter of preferance,be it mice,mouses,meeses or mooses because not any one of them is said to be wrong.