If you’re familiar with Windows XP Service Pack slipstreaming, this is pretty similar.
I’m using Windows XP Professional for this example. It should be similar with Vista etc.
Make ISO image from your Windows 7 DVD with your favorite software. I used CDBurnerXP.
Save install.wim somewhere on your hard drive from that ISO image or straight from DVD.
Download Windows Automated Installation Kit for your OS (Windows 7, Vista, XP).
Start AIK Deployment Tools Command Prompt from Start menu
cd <path where you saved that wim file>
 
Mount the WIM image with write permissions:
imagex will tell which number is which Windows edition if it’s not found. I tried it first with just number 0. Number 4 is in this case Windows 7 Ultimate Edition 64 bit.
imagex /mountrw install.wim 4 c:\wim
 
Add as many drivers as you like by using DISM. If DISM says that files are essential for booting but drivers are unsigned, then add /forceunsigned parameter.
Here’s example for nVidia nForce drivers (Installer EXE extracted with 7-zip): SATA/SATARAID/IDE/Ethernet/etc drivers:
cd c:\dl\15.51_nforce_win7_64bit_whql\ide\win764\
dism /image:c:\wim /add-driver /driver:. /recurse
 
cd c:\dl\15.51_nforce_win7_64bit_whql\smbus
dism /image:c:\wim /add-driver /driver:. /recurse /forceunsigned
 
cd c:\dl\15.51_nforce_win7_64bit_whql\smu
dism /image:c:\wim /add-driver /driver:. /recurse
 
cd c:\dl\15.51_nforce_win7_64bit_whql\ethernet
dism /image:c:\wim /add-driver /driver:. /recurse
 
..and so on for all needed drivers..
You will need to expand unexpanded driver files in some cases. Drivers are not expanded if filenames in driver directory are foo.dl_ and not foo.dll etc.
Here’s NVidia GeForce driver sample for you (Installer EXE extracted with 7-zip)
cd c:\dl\191.07_desktop_win7_winvista_64bit_international_whql
mkdir c:\displaydriver
expand *.* c:\displaydriver
 
and then
cd c:\displaydriver
dism /image:c:\wim /add-driver /driver:. /recurse
 
Save the WIM image with new drivers:
Unmount and commit (commit = save)
imagex /unmount /commit c:\wim
 
Add the install.wim back to the ISO image with your favorite ISO handling software. I used UltraISO. Make sure that the DVD is bootable. Burn ISO as new DVD yet again with favorite burning software (CDBurnerXP).
Boot and enjoy your new Windows 7 with correct and working drivers.