I've got a whole stack of petzle attache beeners I bought cheap. They're smaller than normal beeners and light. The attache 3d is only 55g vs the mighty mouse 86g. I've never used a mighty mouse but they look fairly similar in size. The petzl is screw gate vs the mightymouse quad lock, but the thread is very fine. The petzle biners can be had for about half the price of the mighty mouse here in aus. The petzle is only rated to 21kn vs the mighty mouse 25kn from memory though. I use the smaller beeners pretty often.
Shaun