Solution when emulator is running -
Do not close the emulator until you are done with all build testings :-)
Simply run your android project and never close the emulator window until you are done with your work for the time, i am working with Eclipse and retest app builds as fast as we do with J2ME. All work the IDE has to do is upload/update the apk instead of relaunching of the emulator window again and again.
Solution #2 - Use Android-x86 in VirtualBox (or VMWare etc).
I don't want to write same thing which someone has already done. Please read the process in this page how to setup android in VirtualBox and use it for development.
Now, most probably you will encounter "where is Host-Only adapter" option?
For that, Go to
File -> Preferences -> Network -> Add new Host-Only Network -> vboxnet0
Now upon selecting host-only network will show vboxnet0 instead of "no item selected".
Happy Droidevelopment :-)