Rogue like Gish Character

[BIGMamaSloth]

I was planning on trying to make my first gish, but I'm not thinking just warrior mage, I was thinking more rogue mage (not one hundred percent sure this is actually called a gish at all). So My first thought for supernatural sneak was psychic rogue, but I asked my DM about psionics, and they just so happen to not exist in his campaign setting. Spell thief looked alright in concept but it's looking like there might not be any Full arcane casters in the party, which will probably make it less optimal. So on topic, Is there one solid base class for this type of thing, or am I looking at more of a class1 x/class2 x/ PRC x kinda deal? Ive heard arcane trickster is a bit of a trap. Sorry for so many questions, I think I'm rambling a bit at this point.

tl;dr: What's a decent build or class for a Sneaky Arcane Caster?

[veven]

Unseen Seer (complete mage IIRC). It's pretty much exactly what you're looking for.

One issue is that it lowers your CL by 3 (it still progresses casting, it just has a weird class feature that raises your divination CL and lowers your others, it's easily overcome by Practiced Spell Caster).

I played an Unseen Seer with the acidic splatter reserve feat and Hunter's Eye spell (from advanced learning). Lots of sneak attack and full wizard spell casting delayed only by 1 level (depending on your method of entry I suppose). It's awesome.

6 skill points/ level too!

[Godskook]

The build I like is:

Rogue 1/Wizard 4

From there, you can go enter Unseen Seer and/or Daggerspell Mage. That alone would make a viable build, but from that base, you can weave in Spellwarp Sniper, Arcane Trickster or a few others as well. Focused Specialist and Abrupt Jaunt on a conjurer specialization are great choices.

Side Note: Arcane Trickster is a trap only if you try to enter it directly. If you find a way to keep 9ths in a 20 level build, its a perfectly viable option.

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What others might suggest is Beguiler, which is viable and quite arcane-rogue-ish, but is only tier 3 and won't fill the "full-caster" role like an actual arcane rogue would.

[Randomguy]

Many skillgish builds take a level of spellthief instead of rogue and the master spellthief feat, so they don't lose any caster levels and they get to steal spells, as well.

A less optimal alternative to the standard unseen seer build is going daggerspell mage. You get a bit more durability and a few cool abilities, but it's a bit harder to get in. You also lose a caster level.

[BIGMamaSloth]

The build I like is:

Rogue 1/Wizard 4

From there, you can go enter Unseen Seer and/or Daggerspell Mage. That alone would make a viable build, but from that base, you can weave in Spellwarp Sniper, Arcane Trickster or a few others as well. Focused Specialist and Abrupt Jaunt on a conjurer specialization are great choices.

Side Note: Arcane Trickster is a trap only if you try to enter it directly. If you find a way to keep 9ths in a 20 level build, its a perfectly viable option.

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What others might suggest is Beguiler, which is viable and quite arcane-rogue-ish, but is only tier 3 and won't fill the "full-caster" role like an actual arcane rogue would.

I'm not concerned with filling the full caster role by any means. or even getting ninth level spells. I was more thinking of a rogue that can shoot out the occasional scorching ray, fly spell, or invisibility. The unseen seer looks great, and so does spellwarp sniper. I'm getting lots of fun Ideas from this.

[veven]

I'm not concerned with filling the full caster role by any means. or even getting ninth level spells. I was more thinking of a rogue that can shoot out the occasional scorching ray, fly spell, or invisibility. The unseen seer looks great, and so does spellwarp sniper. I'm getting lots of fun Ideas from this.

My aforementioned Unseen Seer also had some Spellwarp Sniper levels, super fun stuff.

[Godskook]

Many skillgish builds take a level of spellthief instead of rogue and the master spellthief feat, so they don't lose any caster levels and they get to steal spells, as well.

The primary argument against the spellthief route is that it costs both skills and skill points, and some of them are almost entirely rogue exclusive(barring factotum)

A less optimal alternative to the standard unseen seer build is going daggerspell mage. You get a bit more durability and a few cool abilities, but it's a bit harder to get in. You also lose a caster level.

Daggerspell Mage is 'optimal' enough, and "plays nice" with unseen seer levels.

Also, it should be noted, that Rogue 1/Wizard 4/Daggerspell X/Unseen Seer Y is only down 1 spell level and no CL due to practiced caster, as long as you take no more than 8 levels of Unseen Seer.

@OP, a useful trick with Unseen Seer is to pick up the ranger spell from the PHBII that gives SA/3CL, which on a full-caster build, means you're often times dealing more SA per attack than a same-level rogue would be.

[Rejusu]

Factotum (Dungeonscape) might fit what you're looking for. They're stronger skill monkeys than Rogues are (all skills are class skills, that's right. ALL OF THEM), they can add their intelligence modifier to pretty much anything including strength and dex checks. Oh and they get spells up to 7th level, but they cast them as if they were spell-like abilities which means no spell failure chance when wearing armour. They can also heal and turn undead from 4th level, limited uses per day though. At 19th level they can even imitate class features of other classes.

You lose sneak attack (well, you have to spend your resource points to use it) but Iaijutsu focus can substitute for it and you still have trapfinding.