the problem I mentioned regarding "stupid" Bounding Boxes in PS file in my last post was in fact already known:
- when using the option *text.usetex=True* in my matplotlibrc I should have checked which version of ghostscript I was using since that option requires to have a recent one. I had 7.07, and now switched to 8.51 after downloading/compiling the version available on the web: my problem is solved and my ps/eps files created with a savefig() in matplotlib look great.
Thanks a lot to Darren Dale for pointing out this to me, and sorry for the trouble I caused. Hoping this post will help future beginners like me!