We used to use the media droid 90's directly from DS but they stopped selling them. We have had very good luck with cheap 25 dollar android boxes. 1g/8g seems to be able to run our basic campaigns just fine.
I just purchased 20 MXQ S805 Smart TV BOX Android 4.4 Quad Core for $20 each. There are several versions of these boxes - some have an on off button and some just launch when connected to power. Never know what bloatwhere is going to be on the device but most if not all can be uninstalled to free up some memory. If you want to get really fancy with auto restarts and timed cache dumps you can root them
Also the mini android sticks work well and most can be powered off of the USB port on the TV. That is nice because the client can fix most lock ups simply by turning the TV off and back on.
Call me if you have any questions.
Paul Wheeler
Local Business Patriots / Email to my TV
mr.paulwheeler@gmail
636-368-7705