A script that will grep your ~/.ssh/config for a certain expression, then creates a tmux session with a ssh session for each host matched. It's not pretty, there's lots of room for improvement, but it does the job.

tuxedo.sh

#!/bin/bash

#
# tuxedo
# Creates a tmux session with hosts grepped from your ~/.ssh/config 
# 
# Created by: Caio Correa <[email protected]>
# Named by: @xfer
# Last Updated: 2013/06/06
#
# PROTIP: Add aliases for the most used sessions in your bash(rc|_profile)
# alias secrprojects="tuxedo -o staging -i xen,old PROJECTX projx projy projz
#

function usage() {
    echo "${0##*/} -dh [-c config/file] [-i ignore1,ignoreN] [-o only1,onlyN] <SESSION> <prefix1 [prefixN]>"
}

function print_help(){
    usage
    echo
    echo "REQUIRED PARAMETERS:"
    echo -e "<SESSION>\t\tSession name."
    echo -e "<prefix1 [prefixN]>\tPrefixes that will be matched to the .ssh/config."
    echo
    echo "OPTIONS:"
    echo -e "    -c\t\tConfig file. Default: ~/.ssh/config."
    echo -e "    -d\t\tDry Run. Prints the parameters and matches, then exits."
    echo -e "    -h\t\tPrints this help."
    echo -e "    -i\t\tList of ignored statements separated by commas."
    echo -e "    -o\t\tList of required statements separated by commas."
    echo
}

function error() {
    echo $1
    exit 1
}

function dry_run() {
    echo sshconfig = $sshconfig
    echo ignores = $ignores
    echo only = $only
    echo session = $session
    echo prefixes = $prefixes
    echo hosts = $hosts
}

sshconfig="$HOME/.ssh/config"

# Check if tmux is installed
hash tmux 2> /dev/null || error "tmux is not installed"

# Check if there is at least one parameter
[[ "$#" -eq 0 ]] && usage 

# Gets options
while getopts ":c:dhi:o:" option; do
    case $option in
        c) sshconfig="$OPTARG";;
        d) dry=true;;
        h) print_help
           exit 2
           ;;
        i) ignores=$(echo "($OPTARG)" | tr "," "|");;
        o) only=$(echo "($OPTARG)" | tr "," "|");;
        *) usage
           echo "Invalid Option"
           exit 1
           ;;
    esac
done
shift $(($OPTIND - 1))

# Check if $sshconfig exists
[[ ! -a $sshconfig ]] && error "The file $sshconfig does not exist"

# Check if you have the session name and at least one prefix
[[ "$#" -lt 2 ]] &&  error "Please provide the Session name and at least one prefix"

# The first parameter should always be the session name
session=$1
shift

# Parses the remaining variables to a grepable format
prefixes=$(echo "($*)" | tr " " "|")
hosts=$(egrep -i --color=never "host $prefixes" $sshconfig | awk '{ print $2 }' | sort)

# If there are no matching host, exits
[[ -z "$hosts" ]] && error "There was no match in your hosts for the provided parameters"

# If there is an ignore or only clause, apply it now
[[ ! -z $ignores ]] && hosts=$(echo "$hosts" | egrep -v "$ignores")
[[ ! -z $only ]] && hosts=$(echo "$hosts" | egrep "$only")

# if dry run is set, only prints the variables
if ${dry:-false}; then 
    dry_run
    exit 2
fi

# Change Tab Name (
echo -e "\033]0;$session\007"

# If there isn't already a tmux session with the $session name, creates one
if ! tmux ls | egrep -q "$session:"; then
    tmux new-session -d -s $session || exit 1

    # For each item, creates a new window and ssh the host
    for host in $hosts; do 
        tmux new-window -t $session -n "$host" "ssh $host"
    done

    # Housecleaning
    tmux kill-window -t $session:0
    tmux select-window -t $session:1
fi

# Attach the session
tmux attach-session -t $session