A hatchling? I'd give it a 10, probably. It's about on par with a 6th or 7th level fighter with the half-celestial template. Except that it's strength is a little lower. The hatchling certainly shouldn't have been breathing paralysis gas every round, though -- there's a 1d4 round delay. A baby dragon familiar is kinda cool, though. I'd definately require taking Leadership at the very least, though.
I have no clue what the article says they are, but someone will have probably posted that by the time I'm done typing all this.
Dragon CRs are really wonky -- one explanation I've heard for them is that the CR assumes a party that is specifically prepped for fighting the dragon and is managing to engage the dragon in ideal circumstances. As that's not at all what the heck CR is supposed to represent, using the dragon's CR as a basis for determining its ECL doesn't work.
I'd go with HD + what do it's other abilities make it comparable to? So a great wyrm red would be 40 for HD + 19 for being a 19th level sorcerer + a 5 for its abilities beyond those two things for a total of 64. A juvenile blue being a ECL of 20 sounds about right.
Hmmm. I wonder how close my estimate for the GW Red is to the article's estimate?
