There is also the sense that we need 'bridge' fuels - something to tide us over until some long-term yet to be developed transportation infrastructure is developed.  Bridge fuels would be things easily adapted to the existing rolling stock.   Examples of bridge fuels would be:

1. Biofuels, which as you point out don't scale well.  There are ideas out there for how to improve this situation, but until those are proven, we cannot jump on that bandwagon.

2. Coal-to-liquids.  Technically feasible, but serves to deplete our coal reserves rather quickly.

3. Tar sands/oil shale.  Unclear as to whether this will ever be economic.  Enormous amounts of natural gas are used, and given the current natural gas situation, it seems unwise.

4. Plug-in hybrids.  The idea is that people can plug them in and draw most of their transportation energy from the grid, which would enable other stationary technologies to supply the actual energy.
   

In the longer term, there are several possibilities.  All of these involve a storage technology which is portable, and drawing energy from the grid (which would have to be augmented - ideally with renewable technology).  For personal transportation, possibilities include:

1. Hydrogen is frequently touted.  Technical breakthroughs are needed in two areas before H2 cars are a realistic possibility - fuel cells, and gas storage.  There is also the question where the H2 comes from in the first place - H2 is really an energy storage medium like a battery, so you still need energy from other sources.  Some have argued that due to the inherent losses of creating the H2 and then using it in a fuel cell, that a regular old battery powered car would be more efficient.

2. Non hydrogen fuel cells.  Engineer-Poet seems to like the Zinc-air fuel cells, which on paper look good.  The company that is developing this technology is on very shaky ground financially (unrelated to their fuel-cell work).

3. Electric cars.  Technically electric vehicles are available now, however they are slow and have limited range.  In the past battery technology has been frequently cited as a limiting factor, but advances are being made which may improve this.

4. Some argue that if the scalability problems of biofuels are solved that these can be a long-term solution.  It remains to be seen whether this is possible or not.

5. Far fewer cars.  If none of the above work out, the reality is that we would end up using cars a whole lot less than we currently do, and rely more upon public transport, bicycles, or foot power.
   

It is also possible that there would be a reversal of globalization - a localization if you will in order to help control transportation costs.  This might mean for example that in the wintertime it would no longer be possible to get fresh fruit in the grocery stores.  While this doesn't involve a new technology, but some of the business practices  today are predicated on cheap energy.  As energy costs climb, these practices will no longer be economicly viable.

To get an idea of this check out Vestas Wind Systems, the largest supplier of wind turbines in the world.

http://www.cse.dk/kf/kf_aktie_graf?p_stockid=stock.kf.DK0010268606&menu2show=1.1.2.4.

versus Suncor, the most successful oil sand company in Canada.

http://finance.yahoo.com/q/bc?s=SU&t=my

From an investor's standpoint Vestas is a nightmare whereas Suncor has consistently rewarded investors.  Suncor is only one example out of about 30 I could name.

Once investors are convinced that they can make good returns on their investments in renewables, then money will start pouring into developing a large infrastructure of renewable energy sources.

This is a misunderstanding of fusion research. None of the research machines built to date were expected to create more fusion energy than was put into them. ITER is the first machine designed with that expectation and there is an excellent chance that it will do so and by a wide margin. The other machines that have been built so far were experimental rigs to allow us to understand plasmas under the conditions required for fusion. Fusion has been produced on a very large scale, in the case of JET 16MW of fusion power at 65% of input power. Many machines have reached, and some like JET have far exceeded all that was hoped of them. Our understanding of plasma physics has grown enormously and experimental results and theoretical predictions are now very close.

It has most assuredly not been 50 years of failure but 50 years of excruciatingly slow success.

However it is very unlikely that fusion will provide significant power on a global scale for another 50 years
but it about the only source of energy that has the ability of providing the concentrated power on a large scale for centuries sufficient to enable a global population near the present size to live in reasonable comfort without destroying  the environment.  

Since 50 years exceeds all but the most optimistic estimates of peak oil, the problem is how do we get from here to there.