My list is very much concentrated on superheavy vehicles, but I've been considering spinning off a more 'mainstream' Dark Mechanicus force from it too. Epic is a much more abstracted game then 40k - the emphaisis is upon formations not individual pieces of wargear.
Reading through the summary in post475, there's certainly some stuff we have that is identical - Acolytes are Heretic Skittari and the Velite Droids are Chaos Androids by another name. The Stitched Horrors are close enough to Chaos Spawn there'd be almost no difference in the Epic stats. (I also have a 3 structure point superheavy version - on a critical hit it pulls itself apart into the correct number of spawn for structure points left).
There doesn't seem to be an equivalent of fast attack chaos hounds, or big mutants(ogryn) in this list and I'm quite surprised to see lots of imperial tanks but no defiler or soul grinder. When I think of Dark Mechnaicus I think of bio-mimicking demon engines stalking the landscape. There's also no flyer, which is obviously a product of 6th edition. Traditionally, the Chaos Altar superheavy unit has had anti aircraft ability in Epic, and I've also added it to the Eradicator vehicle below.
My list is very superheavy focused but it's missing data demons, the Kai launcher and Stitched Abomination.
Data Demons I'm thinking hard about - possibly a small formation of them and the Data Medium, or maybe just include them as an addon to a Acolyte formation.
The Kai launcher's special abilities are too detailed for epic, it'd just come through as a disrupt effect that could be tied into one of the armoured vehicles
Where I'd especially like to collaborate is on the Armoured Vehicles:
This is what I have:
.......TYPE SPEED ARM. CC FF WEAPONS RANGE FIREPOWER NOTES
Impaler AV 25cm 4+ 4+ 4+ Cannons 45cm 2x AP5+ / AT5+ Reinforced Armour, walker
Helldrake AV 25cm 4+ 4+ 4+ Flamers 15cm 2xAP4+, Ignore cover Reinforced Armour, walker
Slaughterer AV 25cm 4+ 4+ 4+ Guns AND 30cm AP3+ /AT5+ Reinforced Armour, walker
Spikes and Blades (base contact) (Assault Weapons) MW, EA(+1)
Wrecker AV 20cm 5+ 6+ 4+ Doom Blasters 45cm 2BP Reinforced Armour, walker
Eradicators AV 20cm 5+ 6+ 4+ Heretek Weapons 45cm AP5+/AT5+/AA6+ Reinforced Armour, walker
Distorters AV 20cm 5+ 6+ 4+ Warp Cannon 90cm MW5+, ignore cover Reinforced Armour, walker
All of these can take a 'bound demon' option that improves their leadership (abominable Intelligence), close combat (CC), (bolter range shooting) (FF), speed (infantry is 15cm) or toughness (ARM) - with fairly obvious links to the gods. MW= macroweapon, really big stuff that ignores armour less then AV14.
The Impaler and Slaughterer are based upon the FW Blood Impaler and Blood Slaughterer. The other names I have made up, so if I could tie them into the warseer codex, it's a nice bit of easy integration.