Whenever I come up with a good idea myself I realise that someone else has done so, but don't despair! It's more important that you are smart enough to invent the wheel rather than be stuck re-inventing it!
I think it's a neat idea, and you could also apply it to a kind of easel mask that would make test strips easy to do. I always aim improperly when I'm making strips, so I have unequal width. Yes, I know I could make an effort, but what's not to like about a gadget?