He did say a few years younger which made me think of Warren but yeah she has too much credibility for a VP role.
Gabbard would be interesting although she is all over the place with foreign policy. Although the melt down from certain people in the media and inside the Dem party would be brilliant, worth picking her just for that. To go from Hilary Clinton & Tim Kane to Bernie Sanders & Tulsi Gabbard is one hell of change in 4 years.
Reasons Raoul mentioned. Bernie said he wanted someone a different gender to himself, someone a few years younger and for that person to carry the progressive vision. All 3 rule Beto out.
Bernie didn't go into any detail why he wanted the role to be for a women and someone younger(Although I don't there is anyone older than Bernie).