Yeah, I was going to chime in with the Sorc -> Dragon Disciple idea too, but I think this is even better:
(assumes Human for extra Feat)
1: Barb 1 -- Combat Expertise, Improved Trip
2: Ftr 1 -- EWP (Spiked Chain)
3: Barb 2 -- Combat Reflexes
4: Ftr 2 -- Str +1 -- Dodge
5: Sorc 1 -- Feather Fall, True Strike (the two 1st level Core spells without any Somatic components)
6: Dragon Disciple 1 -- NA +1, Mobility
7: DD 2 -- Str +2
8: DD 3 -- Str +1
9: DD 4 -- Str +2, NA +2 (total), Spring Attack
10: DD 5 -- Blindsense 30 ft.
11: DD 6 -- Con +2
12: DD 7 -- Str +1 -- NA +3 (total), Whirlwind Attack
13: DD 8 -- Int +2
14: DD 9 -- Wings
15: DD 10 -- Str +4, Cha +2, NA +4 (total), Blindsense 60 ft., Fly-By Attack
... but then what?
5 levels of Barbarian (Barb 7) -> BAB +16, Improved Uncanny Dodge, DR 1/--, not bad but not great
5 levels of Rogue -> BAB +14, SA +3d6, Improved Uncanny Dodge, Evasion
5 levels of Sorc (Sorc 6) -> BAB +13, 3rd level spells, meh
Sorc 1 / Ftr 4 -> BAB +16, 2 more Feats, 1 more true strike each day, meh
Ranger 1 / Horizon Walker 4 -> BAB +16, some nifty abilities like immunity to fatigue
(some cross-class skill ranks) / Horizon Walker 5 -> BAB +15, Epic level you can start on Planar Terrain Types, kinda nifty
Non-Core:
Exotic Weapon Master 2: Exotic Flurry and the one that gives you a bonus to Trip
Half-Dragon Paragon 3: Strong, but also great flavor
Occult Slayer 5: Trip the Wizard!
... but now that I look up at what i've written, I realize that Whirlwind Attack is not for everyone. Some DMs throw lots of minions at you (WWA is good), some throw one or two big hitters at you (WWA is lousy). So, here's an alternate build, made for equally distributing the pain amongst minions (Cleave) or heavy hitters with DR (via Power Attack):
(assumes Human for extra Feat)
1: Barb 1 -- Combat Expertise, Improved Trip
2: Ftr 1 -- Power Attack
3: Barb 2 -- Cleave
4: Ftr 2 -- Str +1 -- EWP: Spiked Chain
5: Sorc 1 -- Feather Fall, True Strike (the two 1st level Core spells without any Somatic components)
6: Dragon Disciple 1 -- NA +1, Weapon Focus (Spiked Chain)
7: DD 2 -- Str +2
8: DD 3 -- Str +1
9: DD 4 -- Str +2, NA +2 (total), Improved Sunder (works equally well on Hydrae and Unholy Swords)
10: DD 5 -- Blindsense 30 ft.
11: DD 6 -- Con +2
12: DD 7 -- Str +1 -- NA +3 (total), Improved Initiative
13: DD 8 -- Int +2
14: DD 9 -- Wings
15: DD 10 -- Str +4, Cha +2, NA +4 (total), Blindsense 60 ft., Fly-By Attack
Note that DD grants you Blindsense 60 ft., so you have no need of Blind-Fight as a Feat. Together with Uncanny Dodge, you are quite tough to sneak up on.
Anyway, hope this helps!
Cheers, -- N