Here's an approach which uses a gradient to fake the line. It works with multiline strikes and doesn't need additional DOM elements. But as it's a background gradient, it's behind the text...
del, strike { text-decoration: none; line-height: 1.4; background-image: -webkit-gradient(linear, left top, left bottom, from(transparent), color-stop(0.63em, transparent), color-stop(0.63em, #ff0000), color-stop(0.7em, #ff0000), color-stop(0.7em, transparent), to(transparent)); background-image: -webkit-linear-gradient(top, transparent 0em, transparent 0.63em, #ff0000 0.63em, #ff0000 0.7em, transparent 0.7em, transparent 1.4em); background-image: -o-linear-gradient(top, transparent 0em, transparent 0.63em, #ff0000 0.63em, #ff0000 0.7em, transparent 0.7em, transparent 1.4em); background-image: linear-gradient(to bottom, transparent 0em, transparent 0.63em, #ff0000 0.63em, #ff0000 0.7em, transparent 0.7em, transparent 1.4em); -webkit-background-size: 1.4em 1.4em; background-size: 1.4em 1.4em; background-repeat: repeat;}See fiddle: http://jsfiddle.net/YSvaY/
Gradient color-stops and background size depend on line-height. (I used LESS for calculation and Autoprefixer afterwards...)