> P10xx and PPC460ex are affordable PPC chips, others are not.

Compared to the PPC460EX (PPC440 core), the newer Applied Micro chips with PPC464FP or PPC465 core are much cheaper.

> IIRC, some P10xx and P20xx are pin compatible.

Yes, P2010 and P2020 are pin compatible with P1011, P1012, P1013, P1020, P1021 and P1022. They all have e500v2 core.

http://www.freescale.com/files/32bit/doc/brochure/PWRARCHQIQSG.pdf

> P2041 has e500mc core (compatible FPU), but not sure how easily
> it fits in place of 1013.

P1013 and P2041 are not pin compatible.

> Any specs around of T1xxx chips yet?

I'm not aware of any.