I think the approach posted of extrapolating the US peak only to regions that have oil makes sense.

And the current approach is valid what it gives is a upper bound on the amount of oil available. Its simple and you can assert with almost a 99% certainty that there is less then 2 trillion barrels of oil remaining. So yes it has merit and is valid as long as you recognize that its probably a good upper bound.

The next upper bound is I believe the approach of extrapolating the US peak to oil producing regions.

Next you get into detailed arguments.

I think that once you consider all the factors we will recover at best another 500 billion barrels of oil period.

Which gives 16 years at our current usage or probably 20-30
in reality.

Once you can no longer support growth in a oil based economy it will rapidly shift to a new economic model or more likely adopt some of the the past models. In general it looks like the new economy will be one based on concentration of wealth and power not generation of new wealth if you can call this new.
The only real difference this time around is that we will have high tech kings. The consumer industry will probably shrink but I think electronics will stay popular since you need to give the masses their circus.

1.) Health Care ( probably continue to advance but subsidized to focus on the health needs of the wealthy.)
2.) Electronics consumer goods continue (Circus needed)
3.) Communications continue to grow ( Post peak they will be even more important)
4.) Military technology ( Massive growth )
5.) Alternative energy
6.) Electric rail transport for the masses and advanced air transport for the wealthy.

As you notice these are all industries that have a low footprint most are "Cyberspace" focused or biological. I don't see any growth in the traditional manufacturing/consumer goods. Its funny that it looks like in the end a small number of people will get their flying cars. For the general population I see a massive move back to agriculture but I'd not call that growth followed by re-industrialization in the western countries to support basic needs ( Kitchen goods, bicycles, clothes,cheap toys etc) this is not growth. Recycling the McMansions will probably be a big industry for a while.

The wealthy get besides the traditional trappings of wealth.
Huge homes servants (slaves)
Advanced health care,Flying cars,Instant advanced unrestricted communication.

The poor get Xboxes and Cable TV and restricted internet access along with either a long rail commute or a small flat in the city. I suspect in a lot of the world poor people will be sterilized probably via sterilization drugs after one child if they are lucky. They will get enough health care to prevent massive plagues along with basic medicine.
Sterilization will be used to punish most breaches of law.

The military gets many cool new toys to keep the status quo.

The middle class will be reduced to the technical and managerial people needed to support the rich, military and oversee the masses.

And we probably will sit here for years until we have two technical breakthroughs

1.) Fusion
2.) A real space elevator or cheap space access method.

And the world population drops back to a reasonable levels.

http://en.wikipedia.org/wiki/Tethys_Ocean

It would be interesting to know how much of the bed of Tethys has not been explored.