Friends with Half The Benefits ...
1h) Elemental Envoy = good enough at level 1, retrain away at level 6 for the Psicrystal
1) Imprint Powerstone
1b) Chameleon Crafting from Dr#349, you qualify for it.
Start flipping Arcane stuff over to Psi, and dump into Repertoire.
7) pick PsyRef power and a nice "talk" with the DM about how you know every power/spell.
But you're almost a full level down compared to the rest of the party,
because of all the powerstones + learning you're doing.
This is all you need on the Erudite side. Keep PrC levels at or below 6.
Beguiler capstone ought to work with psi PR. It absolutely works with Magic Mantle.
And you'll have all those juicy PR powers and SR spells.
So long as Erudite 17 casting levels happens, (Mindbender works here)
you can go non-casting with the other 3 levels.