An outgoing female or a male with a pushover attitude would probably be a good match. You don't want an overbearing dominant dog since Smudge is so sensitive, but one that establishes it's dominance in a mild way should be ok. A second dog with a lot of confidence could actually be beneficial to Smudge because he could consider them a mentor and bond easily. My RB Rottie was very sensitive while my Pit is very outgoing and confident and they made the best pair. They were glued at the hip until Ziggy passed.

Do you have any pics of Smudge?