For a dedicated crafter, why not play an Artificer in the first place? Seems rather strange to use the "second best, and only at high levels" option instead.
...right, you're playing an Artificer in another game. So why did you want to be an item crafter in this game, too, again?
That said, 2 levels of Chameleon is optimal for a crafting Warlock, since you can use the floating feat to pick whatever item creation feat you're going to be using that day, without spending an actual feat. You're a Gray Elf, however, so this won't work.
Seeing how you're not going to want to wait 8 levels for crafting your first piece, how about dipping some full caster, then going into one of the Theurge classes? Either Archivist or Cleric would work nicely for this.
Hellfire Warlock isn't all it's cracked up to be - too much wrangling (and DM intervention, in your case), too little payoff except in pure damage. Leave the damage dealing to others, and try to get some more useful schtick alongside item crafting.