[totaltec]

Worked on this a bit today. To style the popup add this to your altskin.css:

/**
 * Dialog message container
 */
#dialog-message {
  margin: 0 -225px 0 0;
  padding: 0;
  position: fixed;
  right: 50%;
  top: 100px;
  width: 450px;
  z-index: 1000;
}
#dialog-message .box {
  position: relative;
  border: 1px solid #000;
  border-top: 3px solid #000;
  padding: 10px 25px 10px 59px;
  vertical-align: middle;
  text-align: left;
  min-height: 32px;
}

Should center the message, widen it a bit, and push it down 100px- at least this should get you started styling these.

Another place to look for settings for OPC page is /skin/common_files/modules/OnePageCheckout/ajax.checkout.js:

  var opts = {
    message: $(m), 
    showOverlay: false, 
    centerY: false,
    timeout: 5000,
    css: {
      border: 'solid 3px #fff',
      right: '0px',
      left: '',
      top: '0px',
      width: '350px',
      textAlign: 'left',
      backgroundColor: 'transparent',
      cursor: null,
      padding: '0px',
      margin: '0px'
    }