I use Thesis. I wanted multiple blockquotes and tried duplicating original css definitions but somehow none works.
I tried names like blogquote, bquot etc. Then in custom.css I duplicated the original (with slight modifications) as:
.custom .format_text bquot
In my need I have a quote pic, text indented by 50px. But the pic gets overlapped. After every para, a line appears alongside. Here is the pic: