That's quite a list ! I think you're addicted to SEOS building and I'm obligated to refer you to medical help, but I think I'm just going to encourage you and feed your addictions
Most of those are more similar than not, but they also all have their own strengths and weaknesses. COST/SIZE/PERFORMANCE.
Throw this one in the mix too: http://www.diysoundgroup.com/forum/index.php?topic=37.msg267#msg267
OK, here we go.
Fusion Pure - Excellent frequency response, excellent off axis patterns, highest sensitivity of the group, big, costs the most.
Karma 10 - I haven't seen to many details, but Bill Waslo measured it and I recall he was impressed. Quite high sensitivity for the group. Highesh cross over. High bang for the buck.
Fusion 8 and Alpha 8 - I don't have many details for these, but they're mid to top tier component in a small package. I don't think they get all to good of sensitivity or bass extention (again, I don't know to many details) but they are small and fairly cost effective.
My cheap alpha build - Not bad really. Excellent bass extention. Sorta small for a SEOS. But really low sensitivity. Even the Fusion and Alpha 8 are higher sens.
And that little Jack of All Trades 8 - Dirt cheap. Very small. Good bass extention. But has some notable compromises. They're mostly benign, but not dissmisable.
If you can tolerate the size, the 10's has serious advantages. And I don't think the cost is all the different from the Alpha and Fusion 8's. It's a fairly broad comparison, but depends a lot on your requirements. Good luck