Place this in your $PATH, then you'll be able to quickly rebase N number of commits with "git squash N"

git-squash

#!/bin/bash
#
# This is just a wrapper for : git rebase -i HEAD~4

BACK=$1

function die {
        echo "$1"
        exit 1
}

if [ -z $1 ]; then
        die 'You must specify an integer, representing the number of commits to squash'
fi

echo $BACK | egrep -q -e '^[0-9]+$' || die 'Supplied arg is not an integer value'

git rebase -i HEAD~${BACK}