It's in Complete Divine too. They steal spells and SLAs from opponents, similar to a Spellthief.
Ah.
Taking into account the Maskim in the Bestiary and its ability to SA on every hit, I'd hardly say that Void Presence is overpowered for an Immortals Handbook game. (I'm assuming that's the ability that makes every hit a SA.) Level 30 does seem appropriate though.
Oh, for an Immortals game? No, not overpowered. I was talking standard D&D.
I think it's a cool idea, but I think we might have differing opinions on what's too powerful and what's not.

My group likes to optimize with Ascension, which already sets the bar high, and that's the system I design for and how I gauge balance, whereas you have your own modified ruleset, right?
Yeah, I think your idea of "overpowered" is a lot higher than mine, especially if you're using Immortals Handbook rules. Project Phoenix is a lot closer to standard D&D rules, though I'm still getting a handle on balancing epic stuff - RAW epic is so wonky it's hard to tone it down to be "balanced" while still "more powerful than pre-20th level".
Well, it's more to the point that there aren't THAT many concepts for epic feats and class abilities, and you want to avoid an epic PrC being nothing more than a collection of feats.
Well yeah, definitely.
How about the reverse, using Death Attack DC for the spell's DC?
At those levels, spell DC is likely going to be higher. DA DC is 10+1/2 class level + Int mod + mods. Spell DC is 10 + spell level + stat mod + misc bonuses. There are very few things that add to a death attack DC (one feat that I know of, and maybe some class abilities), whereas there's a crapton of stuff to boost spell DCs, and any caster worth the name is going boost his casting stat.
Also, I'm having visions of delivering a Death Attack via Finger of Death.
Yeah, that's kind of what I was thinking too.
Uses per day are SO 20 levels ago.

I suppose if you're going for a more...mellow game, than yeah, some restrictions should apply. I'm a bit loose as a DM when it comes to that (which I make up for by throwing appalling challenges at the party)
Yeah, yeah. It's a lot easier to power
up than power
down, IMO - why don't we make it for straight up D&D, then you can tweak it out for your level of play?
I don't really agree, but that's fine. I wouldn't bat an eye at getting full SA/DA and full Arcane Spellcasting, especially with a rogue's chasis. It's your idea, though. I don't really have super ninja-mages in my setting, which is what I build PrCs for, so I'm just offering input.
That's cool. I'm just tossing out ideas. My line of thought, though, is that a) it's not a pure caster class; b) the character's already getting a boost with the rogue HD/saves (good Ref/Will, right?), and c) it's more of a class centered around assassination and stealth than gaining spell power (like, say, the Archmage), so a stunted progression makes more sense. And, too, I'm just tired of seeing all these full-caster-progression classes.
True, but what's to stop every epic rogue from taking both?
Nothing. Nor should there be. Although personally, I'd either rewrite the VIn, or cannibalize it for this class. It's a mess.
Well, I prefer to not have worthless abilities that lag 20 levels behind my character level at epic, but whatever. I suppose even 1/2 casting can't hurt a rogue.
Depends where you set the prereqs. If you're aiming for L50 entry, then yeah - you'll have to have some serious abilities. I'm not very good at designing for that level of play, though. *shrug* Adding rogue levels to caster level just doesn't make a lot of sense to me.
I'm asking for opinions here. Feel free to disagree and put forth your own ideas. I chose that because it's rather descriptive of what the class IS - it's an arcane assassin/thief. I think. We should really start back at the beginning and figure out an overarching theme before discussing abilities... What does the class do, what is its purpose, and who would be best suited to take it.