I just posted a 3-armed but traditionally-made silver Brigid Cross on Etsy, here:
http://www.etsy.com/listing/51950441/three-armed-brigids-cross-pendant I'm pretty pleased with this. Everything in it is in multiples of 3 (OK, except for the bail, which is singular). It ended up bigger than the 4-armed version, but also lighter, and I think it's really pretty... not to mention conceptually nifty!