Eldritch Trickster (Custom PrC Suggestion)

I have suggested in the past that you enable Arcane Trickster for Warlocks but going the custom PrC route might be better.

While there are arcane/rogue and divine/rogue PrCs, there are no invocation/rogue ones. And since you already made Mystic Knight which basically is Eldritch Knight for non-arcanists, a similar alternative to Arcane Trickster would be great.

Maybe something similar to this but a bit more balanced.

Warlock and Rogue are a natural fit but it's unfortunate that there's no PrCs that combine them effectively.

Daggerspell mage.

Daggerspell Mage doesn't get Disable Device/Open Lock/Search/Sleight of Hand/Use Magic Device which is the whole point of a Arcane Trickster-like PrC. To combine trapfinding/picklocking with a caster.

Unless the description online is out-of-date the daggerspell does indeed help stealthy, but the rogue-ish part of the trickster class (disable device, open lock, slight of hand) is not included in any warlock PrC currently. But to be fair scanning through the PnP classes briefly I am not sure there is a warlock trickster like PRC (could easily be wrong on that one I did only a brief scan of descriptions).

I'd say go with daggerspell for sneaky, if you want the other rogue portions, thats a legit suggestions, but with all the new classes K's working on, I'd say don't expect it any time soon (assuming its something he's willing to do at all)

Edit: I appear to have been too slow in posting :-(

There's one legal PrC I am aware of. The Scar Enforcer from Races of Destiny.

D8
High Will save
Medium BAB
Most Rogue skills except UMD
6 + Int skills/Level
5/10 casting
Sneak Attack 3d6
Hide in Plain Sight
Favored Enemy Elves and Humans
Smite Enemy 3/day
No Arcane spell or caster level requirements
Half-Elf and Non-Good only (the restrictions can be easily lifted)

I have no plans to do anything like this.