Like MDV says, I don't think the Tonelab LE has any ability to take an AUX input.
One thing worth mentioning - the Tonelab uses "Valvetronix", the same Vox modelling technology as used in the Valvetronix hybrid/modelling amps. I went for the Tonelab because it suited my purpose better - I had no need for amplification/speakers with the models.
And I'd agree with Philly - some models sound better with different types of pickups: humbuckers, singles, P90s. This applies to both the Vox and Line6 stuff. On the other hand, I'd say that it applies to real amplifiers as well!
Actually, for me, I seem to recall that the POD XTLive seemed to respond best to a Variax plugged into it... :roll: