Well, for that, you could simply put the following in your Free Nodelet:
[href://?node_id=`parent_id`;displaytype=xml|parent as xml]
then use your browser's "open in new window" function on that link to view
the parent's source during reply/preview.
Well, you know, for one thing as intrigued as I am by the Free Nodelet, up until this evening I had not been able to use it due to... well long story made brief: just me being somewhat of an idiot - I overlooked, well a bunch of things... and I complained to myself: why doesn't the damn thing work? Indeed I was tempted to ask first or later, and I had resolved to do so now, but instead of doing so in a new thread, in this very reply. Before posting, I tried once again and I found out what was wrong. Now I have the thing up and runnin sitting there.
Said this, your suggestion partially solves part of the problem. "Partially" because it takes one click away, but still a view of the source would be better than the xml rendering (I don't know other browsers, but FF doesn't show newlines) of it inside a particular tag... "Part" of the problem because a <quote> tag although not strictly necessarily would be very nice and useful: I still want <quote>, and perhaps a pony. Now, where's <quote>, and where's my pony?