It would be great to have a view of all the Channels that are available and which source(s) might be associated to them in a single view. I haven't tested this yet, but if you add favorite channels for a specific source and that source goes away, will that channel still be a favorite from one of the other sources if they overlap? From how it seems, the favorites are independent to each source, so I would assume no.
for example
[6140] ESPN1 --> ESPNHD (Uverse), ESPNHHD (Comcast) etc