Your procedure seems fine to me, no unnecessary steps there IMO, I would only add that prior to plugging in the modem, the list of running s/w should not include DVD & CDROM s/w, but that is likely covered by disabling autorun that you mentionedUnbricking instructions to follow, I've only had to do this once and was a little panicked at the time (wasn't my modem) so these may not be perfect and might include unnecessary steps.
Download the plain drivers without dashboard here and unzip them.
Unplug the modem from the computer and remove the SIM card. I remember reading that QualComm have some diagnostics modes that are only available before the SIM is detected, so I figured by not having the SIM card in might make these modes available.
Make sure autorun is disabled and restart your computer. Make sure you have no dashboard or other software (anything Vodafone or Nokia, for a start) running that might interfere with your COM ports running, check Task Manager and kill any stubborn ones.
Plug in the modem, hopefully you'll hear the sound of a device being detected. Check in Device Manager for your modem ports, if you don't see them, but do see a Mass Storage Device, follow the steps here and point it at the drivers previously download if required.
As iam3g pointed out, no usb device, no talky-talky, so you have to get the COM port detected before you'll be able to run the firmware update program again.
As for MidnightWizard's idea of looking at Huawei E220 circuit diagrams and swapping a firmware related EEPROM chip, I really don't think that's going to help anyone here unless they happen to be an Electrical Engineer to start with, and then there is still the issue of getting base firmware onto a new EEPROM and whether or not there is a default bootloader that actually loads the changeable firmware - where would one get such a bootloader & PC s/w from if not from Huawei directly? - and it's not like Huawei are just going to email that sort of stuff out to anyone that asks for it...all in all it's not a very practical nor workable solution to Donny31's bricked E220 problem.