For Starters
Alistair,
I think you could do a lot worse than run with the stuff "unhinged" has put up for sale there ... good starting points.
My advice at this point mate is to forget about riding freely thru China ... its a boat load of work. Sponsorship too is really only going to be worth the effort if you line up a lot of publicity and media interest in the first place.
I would take some russian lessons at university ... just "sit in" on the classes unofficially, so you dont pay for it and dont get examined on it ... its kinda what we did, and you get free lessons that way.
A couple of young english guys travelling around Russia on motorbikes (and speaking some Russian) ... believe me you will have a ball ... and so will the Russian girls you meet.
Getting across China to India will be the hard part for you. There are a couple of options open to you
(1) Fly the bikes from Central Asia to Pakistan ... Tashkent or Almaty to Karachi should be feasible.
(2) Cross China on the bikes, with a guide ... if you keep it short n sweet ... ie. enter at the Torugart pass that connects Kyrghyzstan with Kashgar in western China, and exit at the Khunjerab pass down the Karakorum highway into Pakistan ... your time in China could be kept to as little as 3-4 days. That would minimise the costs significantly. You would have preserved the integrity of the travel by motorcycle concept, and you would have ridden in China.
(3) Cross from Central Asia to Pakistan via either Iran or Afghanistan on the bikes. Iran on paper sounds the easiest ... cross from Turkmenistan to Iran, and then from southern Iran into Pakistan. I havent ridden in Iran, but all the people I know that have report it's people as being infinitely more friendly and hospitiable that they had feared. Alternatively cross from Tadjikistan into Afghanistan would be more interesting, especially if you were trying to keep media and sponsors amused. An old Aussie contact of mine, Peter Forwood, recently (2005) rode into Afghanistan alone, on a Harley. You can read more about that here:
http://www.horizonsunlimited.com/forwood/afghani1.shtml
In that way, you could get to Kabul, and from Kabul the Pakistan border is not far away.
Also as I mention on my website mate ... get a copy of the Terra Circa or Mondo Enduro DVDs ... they are made by guys on the cheap riding around the world and will give you some idea what its like... they are great fun to watch and will inspire you and your mates no end.