If you're not adverse to some minor refluffing, Fist of the Forest (CC) and Bear Warrior (CW) complement an unarmed Barbarian quite well. Just say that he hulks out and gains the strength and stamina of a bear, rather than actually turning into one. End with levels in Swordsage for the Setting Sun '* Throw' strikes, Crusader for the ability to heal yourself by hurting others and the Stone Dragon maneuvers, or Warblade for Iron Heart Surge. As for feats, Supreme Unarmed Strike (ToB) synergizes with Fist of the Forest to essentially give you full monk unarmed strike progression. Steadfast Determination (PHB2) substitutes Con for Wis to Will saves. Snap Kick (ToB) gives him another attack but imposes a -2 penalty on all attacks. If you allow 3.0 material, Knock-down (Sword and Fist) allows a free-action trip whenever you deal more than 10 damage.
Consider the following:
Barbarian 4 / Fist of the Forest 3 / Bear Warrior 5 / Crusader 8
Key feats: Power Attack, Improved Unarmed Attack, Great Fortitude (these three are needed to qualify for Fist of the Forest), Extra Rage (CW), Supreme Unarmed Strike, Knock-down, Wild Cohort, Steadfast Determination, Snap Kick, Extra Granted Maneuver (ToB).
This build gets most of what he's asking for by 8th level, but really get's going around 12th. The Crusader levels are just icing, making sure he stays relevant at higher levels.
Have the summoner (assuming it's based on a wizard or sorcerer, not a cleric or the PF class, otherwise consider having the artificer craft a CL8 wand of it and a wand of Animal Growth) cast Greater Mighty Wallop (RotD). This will make his unarmed attacks do up to 12d8 + Str damage (4d6 at level 8, 8d8 at level 12, 12d8 at level 16) triggering a free action trip attempt. When he rages he turns into a bear and gains +16 Str, +8 Con and +2 Dex, as well as all of the goodies from polymorphing into a bear (depending on how you refluff it). He gets level 7 maneuvers with an Initiator Level of 14, with 8 maneuvers and 3 stances drawn from Devoted Spirit, Stone Dragon or White Raven.
One downside to this build is that he only gets a Python from Wild Cohort, so it may not be as effective in battle as one would like.
Barbarian 3 / Bard 3 / Fist of the Forest 3 / Bear Warrior 5 / Crusader 6 also gets level 7 maneuvers, but will only get 3 rages per day, and only 1 until he takes the Extra Rage feat. It also only ends up with 19 BAB. This build will also take Multiclassing XP penalties unless Crusader is your favored class (which means not being a Half-Orc). Consider adding Song of the White raven and Words of Creation (possibly ditching Snap Kick to make room), as well as giving him a Vest of Legends. His Inspire Courage costs him 3d4 non-lethal damage, but gives +6 at level 20. If you allow prefight theatrics as his perform skill, it even fits his character. Words of Creation does require him to be exalted, though, so perhaps that may need to be cut.