After seeing all of these splicing creations, it occurred to me that you could make a knotless prussic type device pretty easily. The thought occurred to me on my drive in to work so I've not yet made one but I wanted to see what you all thought.
Make a nacrabiner/loop shackle in the way that Opie showed (the small spliced loop and the longer single strand before the stopper knot) but rather than using that longer single strand to tie a prussic, you could "bury" your tarp's ridgeline through that strand, rather than having a prussic knot there. I think you would lose less vertical distance from your ridgeline to the tarp's tie out, meaning that you would not have to raise your tarp tie out quite as high.
What do you guys think? Does my poorly worded description make sense?