Sorry for my poor Englsh ...
Because I hope I can divide my work into some sessions: modeling,texturing, rendering ...etc
I am thinking if we can make a "standard plugin" each time that contains only the plugins we need before we launch SU.
Actually I am doing this by a batch file now (I know the interface is ugly):
\Google SketchUp 8\Plugins
\plugins_modeling
\plugins_texturing
\plugins_vray
\plugins_test
------------------- .....etc
for example, if I need to do a render work,
I run the batch file to rename "plugins" to "plugins_00"
and rename "plugins_vray" to "plugins"
and call Sketchup.exe
after the work, I leave SU, the folder will rename back.
I know that is not a ruby issue, but I think maybe it's not a bad idea .. 
Addy