if the goal is to help the user "notice" and "read" URLs, then why not just (for example):
-use another font for URLs, one which mitigate the similarities between characters
-make the URL bar bigger with a bigger font
-use a small popup (à la Wikipedia) that shows the URL clearly when the user hover it. Actually something happens when you hover a link in some browsers, a lost, grey container with a black font appears in the bottom left of the window, it contains the URL of the link.
but if the goal is to setup "yet another input device" for a database of shady URLs and domain names, well... you will surely need to integrate not only with the UI/UX parts of the browser which have the greatest usage share.
or if the goal is to hide one important part of the mechanics of the web (and make software feels even more magic...) then, don't show the URL at all.