Level-adjusted races are generally a poor choice mechanically, particularly in high-level games. The tiefling's meagre racial bonuses pale in comparison to what's available magically at that level. You're almost always better off with the class level.
Humans are always a good choice. The extra feat goes a long way, as does the extra skill point.
Class-wise, you don't need to limit yourself to just a rogue.
Complete Adventurer and
Complete Scoundrel (though less than CV) provide a wide range of rogue-like class options. The Scout has almost all the same skills (and the same skill points) as a rogue, for example. If you want rogue feel with magic, Beguiler (PHB2) is a good choice. Again, many of the same skills, 6 skill points per level, INT-based spontaneous casting from a rather large fixed list. The
Spellthief has some interesting magical abilities in addition to the typical rogue, though their main schtick is rather limited unless you're facing a lot of magic-using opposition. The
Psychic Rogue also provides a bit of magic feel with all the goodness of a standard rogue. I'm playing one right now in a play-by-post game, and so far she's a lot of fun. Kind of like a sorcerer with Sneak Attack
'Course, some DMs have a pathological aversion to psionics...
The trick with rogues is to decide first on the flavor you want to play and build your character from there. Sneaky trap finder? Philandering con artist? Smuggler? Thug? Enforcer? Military Scout? Dungeon Delver? Tomb Raider? Explorer?
best to go with Foctotum for that one |
Jack-of-All-Trades?
I'd be happy to help you build something interesting!
Edit: What resources do you have available to you? The specifics of any given build will be drastically impacted by what books your DM (dis)allows. Typical starting wealth for Level 13?