I would try a barbarian build seeing as you are guaranteed 12 hp a level. Since you have 17 levels to work with you can even afford to take a template like half-dragon, half-celestial, etc. Barbs got powered up in 3.5 and things like Indomitable Will make even a straight barbarian a fairly house build.
17th level human barbarian (with 28 Con)
a. 357 hit points, 408 in a rage.
b. rage 5/day, dont get tired after rage, gain +3 vs Will saves and another +4 vs enchantments (so +7 vs enchantments in a rage).
c. DR 4/-, +5 to AC and reflex vs traps, improved uncanny dodge (21st level rogue to sneak attack him).
Only problem is merely 7 feats (if human). I suggest Track, Power Attack, Improved Bull Rush, Weapon Focus, Lightning Reflexes, Improved Critical, and Iron Will. I. Bull Rush is a little weak, can always substitute for Improved Initiative. Take Leadership if its available.
Get an Adamantine +5 weapon and youre ready to rock.
As an aside I think the dwarven defender build below would have 346 hp with 380 in a stance (and would have 1 more feat over the barbarian [not counting prerequisite Dodge, Endurance, and Toughness]). I feel without some of the non-core feats the defender isn't as viable as it is otherwise and would rather have the barbarian with more hp, more strength during a rage (that lasts 15 rounds and allows you to move vs 14 rounds of standing in the same place). Also, the dwarf is winded after the stance whereas the barbarian isn't. Keep in mind the goal is "race to the finish", dwarven defender (with 20 ft move vs barbarians probable 40 ft move) just seems like the wrong "tough" build.
Technik