I like change WM/DE very often. I like lxde and openbox but I used gnome2 (in the past) and I use rarely kde and play with other WM/DE. Change .xinitrc is easy but not immediate and I developed several years ago a personal shell script. So when I want run lxde:

ax lxde

when I want run openbox:

ax openbox

... and so on.
Almost a year ago I rewrite this shell script to be suitable for distribution, I will be happy if it may be useful for someone:
https://notabug.org/viverna/ax

Execute: ax [your_favorite_wmde]
for example:
ax lxde
ax kde
ax without parameters run last WM/DE or the default.

ax understands WM/DE reading $ETCPREFIX/etc/ax/client
(for me $ETCPREFIX is /usr/local).
"client" file has a very simple syntax:
NAME_WMDE NAME_EXECUTABLE MULTIPLE_ARGS_EXECUTABLE

for example:
https://notabug.org/viverna/ax/src/master/etc/client

usage:
https://notabug.org/viverna/ax/src/master/USAGE.txt

I use everyday and works well but it is my personal case and it needs more tests.

Someone is interested in trying it out?