Theres a surprising number of games that are trying it.

http://store.steampowered.com/app/24400/

Thats basically Total War in the legend of King Arthur. Has a campaign map, turn based. Has battles which go the same.
Made by Neocore, and all they do now is basically the same thing. They had a crusader one, new one coming out, same thing basically.

Problem is, the battles suck.

Real time version of TW campaign map:

http://store.steampowered.com/app/90100/?snr=1_5_9__13
Thats a really fun game by an indie dev.

Most games just don't combine both elements.