Wow, I checked out the site, surly a GTA0s board won't cost 500 pounds?! And, I was looking at ebay, N900 cases can be bought for less then $20 from China. I think software will be the part that requires the most time. Maybe you should raise enough money to buy 100 boards and cases and to hire a couple devs. I think $300 is the most most people will spend, so try to keep it around there.