Well if Eochi spawned at least we needn't worry that they'll only spawn in CoH zones (phew!), so try put out a call on the badgehunter channel and see if anyone pipes up.
Good luck!
I managed to take him down in Sharkshead Isle (bottom right hand corner of map)
A few hours later I took another team to find him and he had vanished!!
May not help much but he definately spawns in CoV!!
Echoi seems to be everywhere though!!!
seen him twice in Sharkshead now - different places tho
A 40 man gank squad has just slaughtered him at the Hell Forge
He was in Sirens Call earlier too
Sharks its 
thanks guys at work now but will hunt him down tomorrow morning if i can get enough plp together
Sharkshead and sirens seem to be the only places any that i have heard on cov have found him. spent 4hrs killing Ecohai yesterday in st martial and not 1 spawn of jack this leads me to belive that he hate us and dont wanna show his face.
A resent post on the defiant villains came to the conclusion that he only spawns in the morning the midday and the evening.
but its safe to say if ecohai is around then jack wont be , managed to kill him twice in sharks also on the opening day of the event but not seen him once since. heroes dont seem to be having as many problems with this as by watching the badge hunters channel i wittnessed 6 spawnings of him in the space of an hour.
For now id say ya best bet is either grandville (forgot to mention teams done him in the fab also on villains union)
or sharkshead.
I will be keeping my eyes peeled and informing everybody that i can when he spawns keep up the good work guys and GL
He's the only one I need to get too now, at least on Gravecall 
, helped take down a load of Eochai so hopefully tonight...
Woot got him in sharks - along with a mini army of about 50 villains .
Heros
Max Powerz: Lv 50 Tanker
Villains
Max Khaos: Lv 50
Overlord of E.V.I.L.
My Brute - http://maxy-khaos.mybrute.com/
LF SG! Arc ID# 193083
I would like to thank everyone who waited while we got so many people the badge. I was in the original team that was killing eochai in sharkhead and after the 4th kill we managed to spawn jack.
I managed to get alot of my friends the badge via channels and coalitions shouts.
Was good seeing villains working together for once in a large scale. Wish we had a hami raid to organise be fun to see how it would work out.
FireBlazer Level 50 Fire/Fire Blaster
New Blood Foundation/Rebellion
Dark Merchant Level 50 Ninja Stalker
Bloodine
Global Chat: FireBlazer
Yeah, that was fun, in spite of the serious lag and Jack constantly disappearing as a result, most villains I've ever seen in one spot, and in spite of the numbers every last one of us got the badge. 
got all the badges bar jack has anyone seen him in any zone