As previously mentioned, the Steel Dragons chapter is one that could be represented by Codex: Space Marines or Codex: Space Wolves. They each have their points going for them. Codex: Space Wolves covers a lot of things I'd like for the chapter: a Dreadnought HQ choice, cheap and versatile Devastator variants, Venerable Dreadnoughts in Elite, and Drop Pods all around.
They also have weird choices for troops where I'd prefer more standard Tactical Squads or Sniper Scouts. There's also the issue of Acute Senses and Counter Attack and many other extra bonuses that don't fit into my idea for the chapter. All in all, Codex: Space Wolves is a very characterful codex. . . . Too much of the wrong kind of character for this chapter. So we go with 'Nilla Marines.
After giving C:SM another more thorough look-through, I've come up with these choices as the most fitting for the army:
Master of the Forge
The 3 Dreadnought variants
The 3 Dreadnought variants (if using MotF)
As you can see, I'm waffling a bit on the "no vehicles" concept. I've been moving closer to a "no transport" concept recently. The Steel Dragons pick their ground to stand on and stand fast.
I'd want to add some new units to add flavor to the army. In the HQ section I'd add the Imperator Dreadnought, Chapter Master of the Steel Dragons. It would be similar to the Space Wolves' Dreadnought HQ Bjorn the Fell Handed except some changes to make it more shooty. I'd also open up Devastators as Troop choices and give them Blood Angels pricing for heavy weapons.
Next, I'd add a new Heavy Support choice to replace Devastators moving to Troops. It would effectively be a Devastator Veteran Squad (Dragonguard Veteran Squad is my working title). Price them at 25 points a model and standard SM wargear and stat line. Increase BS to 5 and Ld to 9 (while keeping Attacks at 1--Sgt still gets 2). But give them all Relentless and the option for any model to replace their Boltgun as you can for Devastator squads at regular C:SM prices. So we'll put the base cost at 135 (the extra 10 is for the Sgt's extra attack) and just like any Vet Squad you can take another 5 up to a total of 10. Yes, that's a lot of mobile, accurate, and heavy-duty firepower, but at 40-60 points per heavy weapon it's also expensive. Maybe a little too expensive. Maybe.
But enough fandexing. I'll go work on some background fluff for the chapter.