QuiQuoter V1.0.2 - Experimental Plugin

Monarch

Add code as user script to GreaseMonkey or any supporting extension. (only tested on chrome)

While composing a message (The composer must be open or you get an alert)

Select some text you want to quote.

and press
### ALT + Q

support partial quotes and preservation of structure
code quoting works but not 100%, < > and other stuff generate as html entities (>)
some onebox support
unstable/experimental
discourse still can't render nested quotes properly you can have that fixed by combining it with the Quotes Fixer plugin)
http://what.thedailywtf.com/t/quotes-fixer-client-side-plugin-v2/47582

A partial selection of a quote preserve quote nesting in reply

Play with it, Love it, Hate it.
It is Experimental and I have no plans to improve it or maintain it further.