Titus has feed gates. I could never find the "sock keepers" people mentioned. CCI Phantom Parts and Goodies : Celanis Paintball, Online Store
If you make your own feed gate holder, leave a little room for the ears to fold in, but try to keep a smaller bore below that to fit a 10 round tube, it makes a nice fit if you need to leave the tube hanging. If you don't want to leave the tube hanging all of the time, make sure you have room for 10 balls, the gate ears, and a few extra balls (so that you don't have to be empty to reload, aka "tactical reload"
You know, very-old school includes 20-30 round stick feeds. I used to have a paintball tournament shirt with an image of a player with a 20 round stick feed.