I think the status you're talking about is the one we assign for our internal workflow, and for API purposes the only type you'll ever see is "complete."
For example:
<revision size="3952" annotations="0" status="complete" id="5" commit-time="2013-11-18T22:03:31Z"
The only thing that's likely meaningful to you there is the commit-time, though you could alternately use ID. We (and this is the very presumtuous royal we, as really at the moment it's largely Molly and Michelle who do the tagging) set a bill to complete when all the additional tagging that can be done is complete. Only bills marked so are exposed to the API and outside world. It is possible for a bill to be marked complete and more changes made to it, so for that purpose the commit time is useful and it's provided in the bill listing so you don't have to re-download things.
Now, if you mean bill status with regards to Congress' workflow, we don't really do any tracking thereof beyond use of the bill's locations. IH/IS for introduced in the House or Senate, RH/RS for reported, pcs/pch for placed on the Senate or House calendars, etc. We tend to focus initially on the introduced bills (unless a bill has skipped introduction and been simultaneously submitted to a committee in which case its first form is reported.
As far as parallel committee drafts Jim can speak better to that level of 'inside baseball,' but I think a lot of committee process doesn't make it out in a timely manner, if I recall correctly.