Want to share my own experience and give heads up to an independent unlocker.
I have the knowledge to go for the unlock method presented here by the OP, but I lack the time to do it and I can probably make the money to unlock 10 phones in the same amount of time I will use to go through this process, so I have decided to unlock the phone through a simple purchase code method and will root the phone later when an easier process comes out. I would be also happy to pay for that since I don't really have time to go through the flash-root process.
So when I first got my HTC Inspire, I went right away to ebay in search of the unlocker I used last time to unlock an HTC Aria. Was surprised to not found the unlocker I was looking for and worst, despite he had over +63k positive reviews, he was somehow been removed from ebay and other unlockers claim he was out of ebay due to fraud. hu?
Anyway, I had his email so I contacted him over email and asked regarding the subject, he said somebody (other unlockers it seems) were accusing him on fraud thus he was removed from ebay.
I got a little reluctant to buy again from him after "hearing the news" but after exchanging few emails with the guy, I told my self "is just 20 bucks for the code, worst can happen if he's not right is I'll loose the money and he'll of course will get the worst advertising"... so, I added him to my gmail chat to have a close talk and after paying him with my google checkout account, 10 minutes later he sent the code over chat and email, which -needless to say- unlocked the phone right away!!!
You can search through my posts on xda-forum and you'll see I recommended this unlocker before, firstname.lastname@example.org
, he is the **** and offered the least expensive unlock code for the Inspire, only 20 dollars, you can pay with PayPal or Google checkout. There is the word outside that he is not right and committed fraud, even this other jealous unlocker post his email address on a scammer's site and I can assure all this is not true at all.
I send others relatives with this guy and all of them got their unlock codes in shape and time. This is presently the least expensive unlocker out there for the Inspire codes.
He also has a web site http://blowfishunlocks.com
, you'll need to register to order the code, but I would recommend do the email thing.
This guy is real, he has a real address and I recommend him 100% for unlocking the Inspire or any other phone.
On a side note, AT&T willnot realease the unlock code after 6 months (new policy) and this is why I had to buy the code. I use this phone in mexican's Telcel GSM and works as charm and I had to manually configure the APN for the 3g.