I have two pairs of needle nose pliers on my bench, one small, one large. Because the jaws taper, you can draw lines across the inside of the jaws with a permanent marker which correspond to whole numbers of 0.1". Makes forming wire jumpers up to 5 holes long really quick.
I suppose actually you could get a triangular pie-slice block of plastic or wood or something and scribe lines across it up to whatever length you want...