No, I haven't discovered some previously unknown CSS pseudo-element that lets you stick a ">" character at the start of every line in a blockquote. It's just a background image, unfortunately.

On platforms without fixedsys it will not look like the same font as the text, and will not line up one-to-one with the lines either, as shown by these screenshots. (Mac screenshot courtesy of iCapture).

I am going to start lobbying the W3C right now to correct this gaping hole in the CSS spec. Of course, MSIE wouldn't support it anyway.