I agree that Vish Kal, Blood Arbiter is pretty good at combo. Sun Titan + Angelic Renewal + Sac Outlet is a good one (and Vish serves that role pretty well). And if the combo plan falls through, B/W sac-matters with a beefy removal-and-sac-outlet-on-a-body Commander is great. You'd have to invest in some good mana rocks (Thran Dynamo, Coalition Relic, Gilded Lotus) and what not but those are usable anywhere even if you decide Vish isn't to your liking.
-Two colors (one will be white)
-Has the ability to combo off if necessary
-Budget build
?
I'd use Vish Kal or Saffi personally
Draft my Peasant Cube.