Ok... I couldn't find what I was looking for. I was sure I saw a feat or Magus Arcana that let you use hexes with spellcombat.
It's been a while since I saw it, possibly was from a forum thread discussing the topic, and a home brew was proposed. I found all the d20pfsrd arcana including 3pp stuff, and it's not there, although they only list 2 splat books, I'm sure there are more.
However, based on the Hex Strike feat, and the Hexcrafter Magus Archetype, I'm asking you to consider this as a Magus Arcana.
Combat Hex (Su)
This arcana allows a Hexcrafter magus to choose one Hex that can be used to affect a single target. When using the spellcombat class feature (including taking the -2 to all attacks), instead of casting a spell as part of the full round action, you may deliver the effects of that Hex as a swift action after a successful hit. You must choose spell or hex for the round before making any attack rolls for the round. The target makes a saving throw as normal for the Hex, although a successful critical hit applies a -2 penalty on this saving throw. You must have the Hex or Hex Arcana class feature, and be at least 6th level to select this Arcana.
This keeps it in line for the Hex Strike feat, and also keeps it from stacking with other swift action Arcana. I didn't think it needed the AoO line, since hexes are SU and don't provoke normally. Since spell combat normally doubles damage on a crit, I thought a small penalty to the save was fair.
Chanting and cursing, you put a hex on your enemy as part of your unarmed strike.
Prerequisites: Hex class feature, Improved Unarmed Strike.
Benefit: When you gain this feat, choose one hex that you can use to affect no more than one opponent. If you make a successful unarmed strike against an opponent, in addition to dealing your unarmed strike damage, you can use a swift action to deliver the effects of the chosen hex to that opponent. Doing so does not provoke attacks of opportunity.
Special: You can take this feat multiple times. Each time you take it, you apply it to a different qualifying hex.
Alternately I had considered making it more like stunning fist, where you had to declare which attack carried the hex that round, and if that attack in the sequence missed it was wasted, but then it shouldn't cost your swift action.
My question, is it fair and balanced? Let me know what you think.