Sold a tripod from our range's 1919A4 at Knob Creek last fall for $350, including T&E. I believe it was an M2 tripod, IIRC
You might try Ohio Ordnance Works
www.ohioordnanceworks.com or the Lomonts
www.klomont.com.
Someone from Ohio Ordnance told me that they had a warehouse full of M2s when I was selling ours.