So... got this thing, how do I develop it, how do I get it setup so I can actually work on this framework?
PYTHONPATH is your friend, first of all.  Set it to the directory you place the portage directory in.
So... gentoo-src/portage/portage <-- rewrite lives here, I place the portage directory in 
/home/bharring/new/portage
then export PYTHONPATH="/home/bharring/new/"


Second, you're likely developing this in your home dir (I know I am).  everything hinges on PORTAGE_BASE_PATH

if a portage_custom_path module exists, it is loaded.  it is the hook for defining your own constants-
PORTAGE_BIN_PATH can be defined
DEFAULT_CONF_FILE can be defined (this is the new config, the example config in this directory)
CONF_DEFAULTS is the meta configuration definition, conf_default_types

these settings all default to PORTAGE_BASE_PATH ; if you define it in portage_custom_path, the settings above will be based off of it.
if no portage_custom_path, then it defaults to "/home/bharring/new/" which probably isn't what you want.

So, how to set this sucker up?
copy ../portage somewhere, copy ../bin somewhere , copy this directory somewhere.
add a portage_custom_path.py to either /usr/lib/portage/pym/ , or /usr/lib/python-*/site-pkgs/ with paths defined to proper locations.
from there, you'll need to mangle a config (in this directory).  If you have the usual defaults for a gentoo system, you won't have
to modify it aside from cflags tweaking, etc.

so... after you've done this, try this- load up the python interpretter, and try this.

>>> import portage.config
>>> conf=portage.config.load_config()
>>> tree=conf.repo["rsync repo"]
>>> pkg=tree["dev-util/diffball-0.6.5"]
>>> print pkg.depends
>=dev-libs/openssl-0.9.6j >=sys-libs/zlib-1.1.4 >=app-arch/bzip2-1.0.2


If you've changed your tree name (my tree name is "rsync repo"), you'll have to change what you try above.
if load_config() bails, then you have your paths wrong.  if you see an error msg upon the initial import stating you're going to get 
/home/bharring/new/ , you've defined portage_custom_path.py incorrectly, or it can't be read/found in a python directory; or, you've 
defined the vars wrong, look at portage/const.py and grok what's going on.

If it fails in the pkg instantiation, either your tree is incomplete (no tree at defined path in config), or that version of diffball 
no longer exists.
Anything else, track down ferringb in #gentoo-portage on freenode, or email ferringb (at) gentoo.org , with the traceback, and I'll get 
ya going.