Could hydrogen motorbikes be viable?

I'm just trying to work out the viability of hydrogen motorcycles.

I found out from various websites that a hydrogen cylinder containing 0.5kg of hydrogen will normally cost around $100 for the hydrogen, plus a further $20 delivery charge and a $14 per month rental cost.

A hydrogen motorbike will have a fuel tank of 250g, on which it could go around 200km.

If it goes say 400km a month (2 fill-ups from one cylinder) then the monthly cost would be $134 for the cylinder (hydrogen, rental and delivery). The price per km is therefore $0.34.

If a similar small motorcylce can do 100 miles per gallon (= 160km per gallon), the gallon costs $2.50 (US prices!) then it would pay just $0.02 per km - 15 times cheaper than hydrogen.

But what if the motorcyclist invests $2,000 in a hydrogen reformer (the $2,000 is just a guess, on the basis that I've read that home combined heat and power plants can cost 4 times as much as a domestic boiler, where a combined heat and power plant includes a reformer and a fuel cell).

The motorcyclist is buying gas at $0.06 per kilowatt hour - the reformer is 75 per cent efficient - so the hydrogen is costing $0.08 per kilowatt hour.

Hydrogen fuel energy density is say 140 megajoules per kilogram - so 1 kg contains 140 megajoules.

To work out a cost of 500g of hydrogen from a reformer: the energy content will be 70 megajoules, or 19.4 KwH, costing $1.55. Much cheaper than the $134 if delivered by cylinder!

So how long will it take for the reformer to pay for itself? If the cyclist is doing 400km a month (on 200km for each 250g fuelling), he will pay $1.55 for hydrogen per month, or $6.25 for gasoline at 160km miles per gallon and $2.50 per gallon.

So by spending $2,000, he saves $4.70 per month, so it will take 425 months, or 35 years, to get back the cost of the reformer. Ouch! And he's got the added disadvantage of not being able to go for long road trips.

But if the motorcyclist doesn't want the trouble of going to a petrol station, or lives in the UK where fuel tax is much higher, or he believes in the hydrogen economy (with hydrogen ultimately supplied by renewable energy, or wants to be one of the first people to do something, or is thinking about 20 years time when oil might be much more expensive or much harder to come by (but there is still a lot of gas) - then it starts looking possible - and the prices are at a level many people could afford.