After one too many wolfpacks knocking me down and gnawing me to death before I recover, I saw Thief-Acrobat II and thought it looked wonderful.
So I'd take Rogue as far as 12, at least (and Rogue 13 gives an additional feat) - but I wonder if other classes would mesh well with it. I'd be pushing my Strength, Intelligence, Dexterity and Constitution anyway (and I have only 28pt at the moment) so if I let Wisdom and Charisma slide, my best options for additional classes are Barbarian, Fighter and Wizard.
If I went Wizard, I assume I'd want an odd number of levels as that's when new spells open up. Levels 1 and 5 give bonus feats, too. I'd be using utility/buffing spells, as the damage spells wouldn't really be keeping pace with the enemies.
Barbarian has Fast Movement at 1 (would that stack with the Acrobat increased movement?) and also Rage, with DR 1/- and Uncanny Dodge (how does that interact with the Rogue version?) at level 2.
Fighter has bonus feats at 1 and then at even levels (how good is the Quarterstaff bonus for Acrobats? Would it be worth it (or at least interesting) to reach 6 in Fighter and Kensai the Quarterstaff?
I'm vaguely considering one of:
Rog12/Bbn3/Wiz5 or Rog12/Bbn1/Wiz7 - Acrobat, Barbarian fast movement, 3rd or 4th level spells (I see Displacement and Haste at L3, Fire Shield and Minor Globe of Invul at L4)
Rog13/Ftr6/? - 13th level of Rogue gives the bonus feat, 6 levels of Fighter for Kensai in staff, then one more level of something - maybe barbarian again for the movement boost
Is there anything particularly wrong or right with either of these? I haven't really settled on a race yet, but I have always liked the extra skill+feat of humans.