So Dragonborn Incarnate Construct Telthor Warforged?
I'd considered something like this (with Warforged -> IncarnateC -> Gravetouched Ghoul), and came to the conclusion that it depends on how the Incarnate Construct negative LA works.
Option 1: Incarnate Construct changes your LA to -2, which is treated as 0 because that's the minimum given in the Incarnate Construct template. When you become a Telthor, your LA is increased to +0.
If option 1 is the case, then a Dragonborn Incarnate Construct Telthor Warforged would work just fine, and be a great +0 LA race option. (As long as the templates are applied in the right order, naturally.)
Option 2: Incarnate Construct lowers your LA (previously +0) by 2. You stay at +0 LA because that's the minimum given in the Incarnate Construct template. When you become a Telthor, your LA is increased to +2.
If option 2 is true, you can't bypass Telthor's level adjustment, since you can't apply Incarnate Construct after Telthor (unless Dustform is used, but that has its own LA +2, so you'd still be at a net LA +2).
As negative level adjustment does not appear anywhere else in the rules, and there aren't any official answers in the FAQ, Ask Wizards, or whatnot, it seems unlikely that I'll determine how it works. (If you've figured it out and can enlighten me, go right ahead.) I may add this
Fey (Living Construct, Dragonblood, Augmented Construct, Augmented Humanoid) to the handy section I have in the big post about questionable rules.