Here is my current level 50 Runesmith build at the beginning of Epic difficulty. This build is focused on melee + shield while going mainly for elemental damage.

Attributes:
I started out with putting points 1:1 into Intelligence and Dexterity. Occasionally I put a point into Strength instead of Dexterity for equipment requirements. These are my current base values:
Strength: 142
Intelligence: 242
Dexterity: 182

Rune Mastery (32):
- Rune Weapon (10) + Magical Charge (13) + Energy Drain (1) + Transmutation (6): My left mouse button skill.
- Sacred Rage (1) + Frightening Power (1): Helpful when it activates due to damage absorption, but most of the time my life stays above 40%. So only 2 points invested.
- Runeword: Feather (3): Strength for holding weapons and nice Offensive Ability bonus.
- Runeword: Absorb (1): I will probably max this later on for more defense.
- Thunder Strike (4) + Unleash (4): My right mouse button skill. A powerful spell for decimating mobs. Get it as early as possible to help you get through Normal difficulty and keep adding points to keep it useful. I will probably max it later on.
- Seal of Fate (3) + Aftershock (3): Really helpful for making especially bosses more vulnerable. I will max this as well.
- Rune of Life (6): Bonus Strength, vitality resistance, and bleeding resistance. Max it early on.

Defense Mastery (32):
- Adrenaline (1) + Resilience (1) + Defense Reaction (1): Nice bonus when activated. Defense Reaction is a good dump for leftover points later on.
- Rally (1) + Inspiration (1) + Defiance (1): Really helpful in the beginning (healing) and for boss fights (total speed). Investing more points into Rally later on will give you a nice healing alternative when your potions are still on cooldown.
- Battle Awareness (1) + Focus (1) + Iron Will (6): Max Iron Will as quickly as possible for the great secondary resistances it offers. More points into Focus later on is also a good idea.
- Quick Recovery (1): Also a nice defense skill to max later on.
- Colossus Form (1): Nice for boss fights, though I found that it is not as awesome with my Intelligence focused melee build as with a Strength melee build (except for the damage absorption of course).
- Armor Handling (6): Max it early for better equipment.
- Shield Bash (6): Max it for decreasing the Defense Abilitiy of your enemies.
- Pulverize (6): Max it for decreasing the Offensive Abilitiy of your enemies.

Notes:
- I played self-found
- I have +1 to all skills and -20% to all equipment requirements from my armor (Somatophylakes Plate; a recent drop from epic Nessus chest)
- I have high life leech: 25% from my equipment (green weapon, green shield, Soul Shiver artifact) + 4% from Energy Drain skill
- A Sabertooth sword with high attack speed bonus from the act 3 tigermen is really useful. Mine carried me through almost all of Normal difficulty. (The Legtip weapon from the spider boss in act 1 is also worth farming.)
- Each elemental damage bonus on your equipment will make your DPS go up noticeably thanks to Intelligence. With all charges from Rune Weapon I currently do 2165 DPS.
- For bosses I activate Colossus Form and Quick Recovery, charge into battle with Thunder Strike, then drop a Seal of Fate on them. Then I just attack with Rune Weapon, using Thunder Strike inbetween when it becomes available.

First of all thank you for sharing you build.
I immediately changed my play style and started using seal of fate instead of the mines.
Since you are the first one posting some relevant points about the runesmith I would like to discuss some aspects of this class combination with you.

The idea behind my build is to permanently use sacred rage (46% total speed and cooldown reduction is just insane). Sacred rage has pretty synergies with both classes:

- fast rune weapon stacks
- both classes offer a total of four attack procs
- Seal of Fate has 9 s cd Aftershock 4 s duration
- Quick recovery 60 s cd 34 s duration
- easy uptime for adrenaline

The only problem is to stay alive... 20 deaths and rising ;)

The things I want to discuss/clarify are the following:
Do you know how rune weapon does interact with shield procs?
What are your plans for the final stats str/int/dex?
What items (int/str) do you plan to wear?
How do you plan to maintain the insane costs of Runeword: Absorb?