This really wasn't working for us so we took a look at Volatility's source code and made some small adjustments. We modified the taskmods.py module that ultimately affects the dlllist module. Normally if you select dlllist plugin with the -h option it gives you various options you can use such as an offset or a pid as seen below:
Now we can simply give it the svchost.exe process by name and get a list of loaded DLL's by processes running by that name. If you have a non-standard svchost.exe process running then this will pick it up as well, but that situation might also help identify a compromise :)
So executing volatility with the following command
vol.py -f 7re-912d4ad7.vmem --profile Win7SP1x64 dlllist -n svchost.exe now gives an output of:
To install it just replace the taskmods.py from your $VOLATILITYHOME/volatility/plugins directory with our taskmods.py.
We have tested it on volatility 2.2, 2.3, 2.3.1 on XP and Windows 7 with no problems.