Puppeteer, Flesh Harrower
You might think that puppeteers in need of muscle take over an appropriate creature, but apparently just spawn some dog-sized murderworms.
Flesh harrowers are 3 RHD small magical beasts. Their stats are actually surprisingly good (14 strength, 17 dexterity, 21 constitution, 11 intelligence, 12 wisdom and charisma), and their natural weapons (one 1d6 bite, two 1d4 'tail blades') and armor (+3) are moderate at best.
The harrowers lack the many abilities of their smaller brethren, with the exception of Blindsight, Telepathy, and a small number of PLAs. Said PLAs are mostly just okay (3/day Concealing Amorpha, Hustle, Mental Barrier, and 1/day Vigor) but are sadly stuck at a manifester level of 3.
In addition, not having limbs sucks a lot more when you're otherwise martially inclined and don't have a disposable host body.
I guess the harrower could make for an okay rogue. An innate invisibility power, blindsight, telepathy, some natural weapons, small size and good stats are hardly bad, after all. On the other hand, limbs are good and useful, so arguments for both +0 and -0 can be made.
For now, I'll go with +0, but that's more to have a relatively moderate starting point than to reflect any real preference on my part. Do discuss.