In the past, I've experienced odd memory consumption issues after upgrading OS X, due to older kernel extensions that were still being loaded. Some of the extensions were for applications that I was no longer using and had forgotten about. You might try listing out all the non apple kernel extensions, then try unloading them one by one to see if you experience any improvement in memory consumption.
To list what is loaded, type the following from a terminal shell:
kextstat | grep -v com.apple
So, each of the kernel extensions, will have a corresponding kext file, located in the default /System/Library/Extensions/.
Then, to unload a kernel extension, type the following:
sudo kextunload /System/Library/Extensions/<NAME_OF_KEXT_File.kext>
If you identify any extensions that are wonky, you then have a starting place to see if perhaps there is an updated version of the application that is more Lion friendly.
Best Answer
Every "Helper" is either a tab, a subframe, a core Chrome process or an extension.
You could reduce RAM usage by uninstalling extensions, or just using less tabs.