Hey, it IS possible! There is no Windows 8 driver because it is not needed. Windows 8 has a special feature for program compatibility. I just installed Tascam US-122 on my Windows 8 HP Pavilion g6 laptop.
1) Go to http://tascam.com/product/us-122/downloads/ and download Windows Drivers v.3.40 Windows Vista and XP driver. Unzip it.
2) In Control Panel/Programs/Programs and Features choose Run Programs Made for Previous Versions of Windows. It will open Program Compatibility Troubleshooter. Click Next.
3) Your US-122 driver will not be listed there, so choose Not Listed and browse for it your downloads folder. You need the .exe file - in my case it did not show .exe extension, but it will show up once you choose it (remember, upzip first!).
4) Program Compatibility Troubleshooter will ask you to select Troubleshooting Option. Click on Troubleshoot Program.
5) When asked "What problems do you experience?" click on first - "The program worked in earlier versions of Windows but won't install or run now."
6) When asked for previous version of windows, choose "I don't know". Another window opens, asking your permission to install Tascam.
7) You will then have to install Tascam. Click Yes throughout.
8) Finally, it is time to plug it in! After you have plugged USB into laptop, go to Control Panel/Hardware and Sound/Sound/Manage audio devices. Choose US-122 as your default device for playback and recording, click Apply, then - OK. Done!