Seems like you might enjoy playing something like LotusHead's Slaver list. Nat Moes talks about it in his recent article:
http://legitmtg.com/uncategorized/the-vintage-advantage-whats-new-in-vintage/

Should cover most of the criteria you're looking for: It's blue-ish, interactive, and utilizes Gifts Ungiven well.

Awesome, thanks for the response. The inclusion of 2x Underground Sea clears up my questions about the mana base.

Going for an early Crucible definitely seems like the strongest line of play, if you don't have the tools to assemble Vault+Key or Tinker+Robot right away. You can either outpace your opponent by reusing fetches, or try to lock them out with your own Strip/Waste+Crucible. The fact that you've had success against BUG speaks to this deck being resilient enough to fight through some mana disruption.

I'm also very intrigued by this Keeper list. Major props on your success with it!
Love the inclusion of creature-hate enchantments like Moat, and The Abyss. They can definitely be great bombs against an aggro heavy meta. Also haven't seen Mind Twist in a long time. Brings me back to the classic Keeper days.

A couple questions/thoughts:  

Do you run into any trouble with your mana base, specifically black mana? You're running 4 high-impact black cards main deck (Yawg's Will, Mind Twist, Vamp & Demonic), plus 1 sideboard (The Abyss). For black sources you've got Mox Jet, Lotus, and 3 City of Brass.
Not having an Underground Sea you can readily fetch out seems like it might put you in a tough spot sometimes: A dead Tutor or Yawg's Will in hand seems painful, especially if one of your City's bites the dust to Wasteland early on.

What are your thoughts behind going with a full set of 4 Drains, rather than 2 or 3 Drains and a 1-cc counter or two?

Do you have any serious problems playing around/against opposing Wastelands/Strip Mine and/or Null Rod? The 4 Drains plus a few other mana-intesive card choices (Moat, Twist, FoF, Mindbreak Trap sometimes, etc), seem like they could become liabilities in-hand for a number of turns after a well played early game Strip effect or Null Rod disrupts your mana pacing/access.

In any case, awesome deck design, and I look forward to hearing your thoughts on your build and piloting Keeper.