With CSS you can basically change font and size:
<input style="font-size:18px;width:85px;font-family:Lucida Console" type="password">
But it is unpredictable what will happen from browser to browser. What you can do is to use a custom font, however, nothing guarantees that the browser will actually use it in practice.
The alternative would be to use a JavaScript to change the characters of a text field, but there are a number of security issues involved.
See some tests on JS Fiddle , remembering that once you get it right Whatever you want, test in another browser and ... Bam! Surprise, all different!