Hi at all.
I have one (or two) question(s):
Can in start Electrum more than once at the same time and open defferent wallets?
Yes. Use File>open or the command line:
electrum -w /path/to/wallet_file
Is there a plan to implement the use of multiple wallets in (one times startet) electrum (like Multibit or Armory)?
Unlikely. Electrum aims to have a minimalistic GUI.