Speaking of which:
Kovid/personal stream of consciousness,
I guess they assumed you were just bundling it -- I see
cherrypy and
html5lib are definitely patched, and
chardet too when I found the previous location.

six.py is identical to
an old version, so it at least could *probably* be unbundled.
Other than that, they change the shebangs to use python2 instead of python (hello, PEP 394

), forcibly declare the sip_dir, and enforce a bunch of Archlinux name and location conventions, which TBH I don't see why that would be a problem.
Regarding translations, the PKBUILD indicates that building it fails, which corresponds to my attempts at setting up a development install on a direct checkout.
Although IIRC I did manage to get the build to go through that one time, by using the resources from the official binaries.
Code:
[eschwartz@arch ~/git/calibre]$ git pull
Already up-to-date.
[eschwartz@arch ~/git/calibre]$ python2 setup.py translations
*
* Running translations
*
Compiling 0 translation files...
Calculating translation statistics...
Traceback (most recent call last):
File "setup.py", line 99, in <module>
sys.exit(main())
File "setup.py", line 85, in main
command.run_all(opts)
File "/home/eschwartz/git/calibre/setup/__init__.py", line 181, in run_all
self.run_cmd(self, opts)
File "/home/eschwartz/git/calibre/setup/__init__.py", line 178, in run_cmd
cmd.run(opts)
File "/home/eschwartz/git/calibre/setup/translations.py", line 243, in run
self.write_stats()
File "/home/eschwartz/git/calibre/setup/translations.py", line 302, in write_stats
cPickle.dump(stats, open(dest, 'wb'), -1)
IOError: [Errno 2] No such file or directory: '/home/eschwartz/git/calibre/resources/localization/stats.pickle'