I have language stickers on my Kensington and on my laptop.
Show Image
(http://www.soulshadow.com/kensington_k64365/ken5.jpg)
I cut them very small, so that only the symbols are stuck to the keys, so there is very little texture difference. They seem to be easily removable, and should do any damage if you clean the residue off. They're basically thin-film transparent overlays; I bought mine on ebay for something like $1-2/set shipped.
I also cut my stickers very small before putting them on my topre. otherwise they felt like they would come off just from my finger brushing up against the side of the key when typing fast. These are also cheap ebay stickers ($5 shipped, i think). They work perfectly tho once you cut them small.
I always thought that kensington looked pretty cool, and I like that it doesnt have an arrow cluster. scissor keys, right?