Here's a tower I whipped up to feed my fish. There are 14 trays that fit in the tower, and I used the EEZYbotARM to pull each cup and dump it into the feed hole of my aquarium.

The video of the pull test can be found here: https://youtu.be/B-0GVr1DBs0

You'll need to create the script and delays to suit your setup. I found assuming each cup is out of alignment and using the arm (like in the video) to align each axis to be very reliable. Once perfected, I'll post it up here.

You can friction weld the sleeve to the base very easily, but it will remain in place through operation without it.

I posted the rotator servo mount design, it can be found here: http://www.thingiverse.com/thing:1198016

The Pololu enclosure can be found here: http://www.thingiverse.com/thing:1190596

The advantage of this design is that it can hold any shape or size of food under 50mm. This is especially handy with my African Cichlid tank (100 gallon), as they eat sticks, pellets, and flakes all mixed together in one feeding. The drums that are out there just wouldn't cut it, so I designed my own.

UPDATE 12/21/15:
-Revised food cup design to prevent cups above from jamming tower
-Added receptacle to toss empty cups into. It's probably cheaper to use a cardboard box, but what would be the fun in that?
-Added funnel I'm using to dump into my 100 gallon aquarium

Here's a video of the whole setup: https://youtu.be/CdDt1R2YPaA

A note on timing/control: I use a mechanical timer to control the lights that switches the outlets on and off. I used a iPod transformer and a USB cable to synchonize the Pololu with the lights. 60 minutes after the lights (power) come on, the first feeding event occurs. I wait 840 minutes and feed one hour before the lights go out. Every day is a new cycle, so 2 loops are run with each day. Remember to power off all channels between loops.

Bench Testing: You'll want to give the servos at least 15 minutes cooldown between cycles when testing "for score". I've noticed the positional accuracy and repeatability goes to pot as the servos warm up. Even 15 minutes is pushing it, as there is some variance in elevation that doesn't exist with the 30 minute wait times I've run.

Enjoy!