Like Deck, I saw that while there were not many three stage fire types, there are a bunch of grass ones. So, I was looking into grass types to see if any of them had some similarities to Pyroak we could use to base things on. Unfortunately, no existing grass line has even remote similarities to the stats of Pyroak, and the closest ones that do are very different in other ways. The main problem we come across is that while most of the three stage lines feature predominantly offensive minded Pokemon, Pyroak is decidedly defensive. Really, about the closest you will get statistically among three stage grass and fire types is something like Meganium, but even that is no where near close.
So, since there wasn't much within those two types, I decided to look elsewhere to see if I could find any similarities. Not many Pokemon have a similar build to Pyroak, and even fewer among three stage families. However, I was able to find one that is a good match: Walrein. Now I know that it might seem like an odd comparison, but, in addition to both being third stage dual type Pokemon, their stats are incredibly similar. HP, SpA and SpD are identical, along with their overall BST. While as far as flavor they are quite different, when it comes to more statistical things, I feel like this would be a good family to look at, very much like the Growlithe/Arcanine family was for Syclar.
Also, Birkal, I'm just wondering what exactly the similarity was you saw between the Cyndaquil family and Pyroak is. Personally I don't see it. However, if there is something there, I would suggest we look at the Charmander line as well. The stats are identical to the Cyndiquil's family for all three stages, and Charizard is both a dual typed Pokemon and with a reptilian based design, similar to Pyroak.
<jas61292> I record everything
<nyttyn> prove it.
<nyttyn> WHAT WAS THE VERY FIRST THING I EVER SAID IN THIS CHANNEL.
<jas61292> [06/02/12 | 12:43] <NyttyN> Huh what deo you know shelll smash did get banned
<nyttyn> well congratulations jas your stalker nexus has reached an all time high.