That was only AFTER he returned to Olympus however.  However, I believe that we could write that in somehow as part of his agenda.  Something like intervening between the powerful and the weak.

This is true.  I'm thinking +2 to power, since I can't see channeling a volcano as adding....control, lol.  More like RAW NATURAL POWER! 

I had forgotten about most of the rotes of earth magic.  I was thinking in the simplest of terms.  If you say, go to use say, FUEGO (well, your own flavor of such a spell) then instead of just a gout of flame, it would be molten lava.  However, taking your example, I think a themed Earth magic would work best.  Afterall, blacksmithing is a metal based art....and metal comes from the Earth.  So have it be along those lines. 

This is exactly why I came to the interwebs for help

Alright, so I've trolled the boards a good bit, and had come across the thread on Sponsored Magic ideas.  One of them really struck me.  Hephaestus.

In many of the RPG's I've played, I've enjoyed the aspect of crafting.  Between making custom gear for myself, and custom gear for the group, it just added that extra layer of cool for me.  Enter Dresden RPG.  Now, the crafting in Dresden is good.  I don't mind havin item limitations in regards to how many and such, although I'd definitely be looking to get more slots.  So, here's the idea that I had...and then the plea for help.

Idea:
To me, there are two things that are iconic to the Wardens.  The grey-cloak, and the Sword.  , the Swords are no longer being made.  So I've got an idea of a character who wants to fill that gap.  Being an exceptional Artificer already, he's checking out all the Old Lore he can.  This is where big Heph comes in.  He's willing to take on Sponsored Magic (whether it's through the template sponsored magic, or emissary of power) for Heph.  What I need, are ideas for what that entails.  The benefits, and the responsibilites.  

I was thinking of having the initial connection be made through an ancient forge that was found....but then the deal is struck.  What do you think?  What help can you give?  As I flesh out my idea, I'll post it up here in the OP, as well as things are brainstormed in thread.

Fluff: All of the other Gods of his Old Pantheon either faded, killed, or whose domains have been taken over by newer Powers, Hephaestus stands alone.  Not quite forgotten...but not worshiped for his artifice and power as he once was.  He came back from exile once, he'll do so again.  He just needs someone to bring him back into power.
Elements: Fire, Volcano(lava,) Metal
Standard Benefits:
Bonus Power:
Cost:

Idea 1: Benefit based on Heph being a God of Fire and Volcanoes.