We’ve just come across a really useful site to bookmark if you own an iphone and it has an accident one day..This site here offers iPhone repairs across Japan including for the iPhone 4 and they say they can do it at half the price of Softbank. They also boast of an 8 hour turnaround. Bear in mind it’s in Tokyo and normal express shipping to Tokyo takes 2 days, but it’s worth a look if Softbank repairs are looking expensive!