Swordsage is a bit less impressive for a solo rogue, since the main boon--Island of Blades--requires a flanking partner. Still, the Shadow Blade feat is quite good so I wouldn't take that off the table yet.
But given the second level Wis to AC, I'd actually suggest a Ninja/Swordsage instead of a Rogue/Swordsage if you were to hypothetically go down the Swordsage route. In this case you would go for high dex and Wis instead of Dex and Int. And while Swordsage and Ninja AC bonuses don't stack, wearing light armor having a nice number of ghost steps is nice.
Edit: bah! evasion requirement. no Ninja/Ninja Spies! >< /Edit
Back to ubernoob's idea though:
Warblade works with Swordsage because there is some Int synergy. Also d12 hit dice. Solo campaign + d12 = longer life.
For Rogue, take Death's Ruin ACF in Complete Champion. Basically you lose trap sense for 1/2 sneak attack dice vs. undead. So a Rogue 4/Swash 3/whatever 5 would have 2d6 against undead.
Smiles' idea isn't bad, but you honestly don't have the good stats to go around. It happens sometimes.