i've never seen them, but if they were avaliable i wouldnt use them. On my electrical engineering course i was taught that you should never use solder tinned wires in screw terminals because in some circumstances they could vibrate loose, or they could snap because it makes them more brittle. this would happen because the screw would tighten up against the solder, and if the wire is then wiggled from side to side, the screw would wiggle too, and work loose, whereas when untinned wires are used, the screw goes all the way to the bottom of the terminal and tightens up against the bottom of the terminal. I think that this is in the IEE wiring regs too, but i'm not sure, i don't have a copy. maybe another user could confirm? Using those crimps would have the same effect. As long as you strip the wire cleanly, to the correct length, and twist the end slightly, and make sure the screw is fully undone before you insert the wire, you should have no conductors poking out.