Re:Biceps - How often?
don't get too hung up on the concept of overtraining, if you feel that you want to include more bicep work, then try it for a month or so and see what happens.
I train all muscle groups twice a week, and since shoulders get hit on a chest day etc. they are probably getting worked closer to 4 or 5 times a week. This works for me, it might be terrible for you. The point is, you won't know until you try.
Current training: 6-day split
Current cycle: Test E @ 500mg per week
Height : 192cm
Weight : 272lbs
Body Fat : 15.4%