I tried out pbuilder. Apart from having to turn down grsecurity
(another bug report) I fought a little with the configuration. Since
pbuilder requires partions mounted without (!) nodev and nosuid I
tried to run the pbuilder on /scr/build (which does not have these
settings) while keeping as much as possible on my Cache partition
(which does have these settings). However, I could not get this to
work, I always had problems about some hard links to beeing set over
partition boundaries.

The following variables where finally all set to my build partition to
get pbuilder to work.

…
#BUILDRESULT=/scr/Cache/Pbuilder/result/
BASETGZ=/scr/build/pbuilder/base.tgz
BUILDPLACE=/scr/build/pbuilder
BUILDRESULT=/scr/build/pbuilder/result/

#specify the cache for APT
#APTCACHE="/scr/Cache/Pbuilder/aptcache/"
APTCACHE="/scr/build/pbuilder/aptcache/"

I probably did not test all combinations, so maybe some might work.

Please:
a) Document the requirement that "nodev" and "nosuid" must not be set
   on the partion for the pbuilder (best in pbuilderrc(5))
b) Document which directories have to be set on the same partition for
   pbuilder to work.

While the first one was easy, the second one was time consuming to
figure out, therefor "minor" as severity. Downgrade to "wishlist" if
you disagree.