[Edit 2019-12-11]: Docker is obviously the way to go now!

Answering to myself, I ended with simple installation scripts like that:

#!/bin/bash

sudo apt-get remove elasticsearch

sudo dpkg -i elasticsearch-0.90.5.deb

sudo rm -rf /usr/share/elasticsearch/plugins

sudo cp -R plugins /usr/share/elasticsearch

sudo cp elasticsearch.yml.0.90.5 /etc/elasticsearch/elasticsearch.yml

sudo /etc/init.d/elasticsearch restart

sleep 2;

sudo /etc/init.d/elasticsearch status

Note that in the elasticsearch.yml file, the cluster name must be different to avoid conflicts:

0.9.5:

cluster.name: cluster_v0

1.7.6:

cluster.name: cluster_v1

And so on.