I've seen the swimming into the sea identify but can't remember if it was on TV or on the internet somewhere, but it definitely exists.
ITV have done a few idents that compliment each other, there are two fish and chip idents, one outside the shop and one inside, and I think there are a few others similar.
The swimming idents were on TV as this clip from The Ident Gallery proves:
And other idents that compliment each other are the Surfers idents.
AlexEdohHD13, Fan of BBC, ITV, and Channel 4 Programmes.