I quite like this design, also Deathstones.

Inspired by the Shards from the Original Mirrodin block. In a set there would be a full cycle of these - one for each colour.

Nice. Has the slight problem that lifelink just isn't quite as good as deathtouch, but the elegance of the mirror here is undeniable.

Yeah I had that feeling too, I just decided that the mirror of the two was just too nice to change them around.
Interestingly, these were going to be part of a cycle of Artifacts (one for each colour) that provided an in-colour keyword ability for C or in an off-colour deck, basically like the shard cycle from Mirrodin - eg Skeleton Shard. After designing these two, I liked the mirror so much that I decided not to do the rest of the cycle (maybe I should post them over in snap for posterity/the curious).