Here are some tempting ones:
Remus Lupin (Harry Potter) / Colonel K (Dangermouse)
Col. Pickering (My Fair Lady) / Eric (Bananaman)
Mr. Darcy (Pride and Prejudice) / Scoop (Bob the Builder)
But the one I really like the look of is:
The Guide (Hitchhiker's Guide) / Titania (A Midsummer Night's Dream)
Surely someone can write that.
I'm not claiming it because I never finished my Picard (ST:tng) / Bender (Futurama) story.
Just be grateful that someone else has already taken Zaphod/Rimmer.