Three years after this question is posted and this is almost within reach. In fact, it’s completely achievable in Firefox 1+, Chrome 1+, Safari 3+ and Opera 15+ using the CSS3 appearance
property.
The result is radio elements that look like checkboxes:
input[type="radio"] {
-webkit-appearance: checkbox; /* Chrome, Safari, Opera */
-moz-appearance: checkbox; /* Firefox */
-ms-appearance: checkbox; /* not currently supported */
}
<label><input type="radio" name="radio"> Checkbox 1</label>
<label><input type="radio" name="radio"> Checkbox 2</label>
jsfiddle: http://jsfiddle.net/mq8Zq/
Note: this was eventually dropped from the CSS3 specification due to a lack of support and conformance from vendors. I’d recommend against implementing it unless you only need to support Webkit or Gecko based browsers.