I'm doing this right now and using my FEV system to evaluate the results.

I've come to the conclusion that, for the vast majority of the tier 5 base classes, a straight gestalt with one of the ToB classes just makes them tier 2. If you use a lesser form of gestalt, pruning off a few abilities here and there, you can keep them to tier 3. What it amounts to is that you can give the base classes FULL maneuver progression and end up in the sweet-spot (tier 3 generally being considered the 'best') for power level.

For Example:
Fighter's FEV value: 51 @ level 20
Warblade FEV value: 126.45 @ level 20
Fighter//Warblade FEV value: 136.45 @ level 20
With a minor modification so that the warblade does not get fighter bonus feats at odd levels - 133.45
That puts the warblade at the very upper edge of tier 3, almost but not quite in tier 2. Because literally all we're doing is adding about 7 feats - the warblade already gets everything good that the fighter does.

Barbarian//Crusader gets you similar results -
Barbarian: 55
Crusader: 115.8
Barbarian//Crusader: 133.3

Monk//Swardsage gets really strange results, mostly because my FEV system doesn't evaluate the Monk class very well. But if you strip out all of the last 10 levels worth of class features from monk (they're neither helpful to the monk, nor are they terribly interesting), then you've got yourself a decent tier-2/3 class. But really, I agree with the board that Unarmed Swordsage does Monk better than the Monk class.