I would recommend something that uses doubled sided tape instead of a permanent modification. Perhaps you can use something like this clip, and if you don't want the whole clip, just cut it at the bend, grind it round so that there are no jagged edges, and then drill it for a lanyard. I would just use the whole clip and fashion a lanyard for it if it were me. Sorry this is the best that I can do:
http://www.niteize.com/products/eclipse
I use one of these clips on my iphone and they are quite fabulous but I'm not using it with a lanyard, but I have put a key ring spring thinggy (one of those round key ring metal spiral rings) around the clip and it has allowed me to use lanyard or whatever else I needed for additional flexibility. This may be a even better option for you. I picked several of these clips up at REI