To make it short (detailing would be very technical), there's no ready made solutions to your wishes yet. Writer2latex + XeTeX is the closest I can think of, but I gave it a look and it looks (given my basic knowledge of LaTeX: I'm really into ConTeXt which goes a different way) definitely requires, even if slightly, getting into the LaTeX code it produces before you can feed it to LaTeX to get a PDF. It would not do everything either:
extrusion (?: do you mean "protrusion" -- let's stick to Adobe nicely coined "optical margins") OK
ligature : that's OTF/TTF job OK
thin space: I assume not if not available in the fonts (usually they lack the "quart de cadratin"--if I remember well--needed for french). Not sure about workarounds such as using non-breaking space + a smaller font (you may certainly find an answer to that on the Web)
drop caps: I have no ideas
Stick to Prince for the time being (there is a free, Open-Source, very well conceived, equivalent called WeasyPrint, but looks not that easy to install). I'm overly critical because I believe typography deserves the best treatment, but it's state-of-the-art on everything else.
There seems to be quite a lot going-on around Open Source electronic publishing: so one can hope a solution might come out in a not too far future. And I'm pretty sure it will have to resort, one way or the other to TeX.