You should be able to create new heroes outside the game, using the XML files. Create a Sovereign and edit the XML to make it a Champion. There is a tutorial by Frogboy somewhere. But inside the game? Nooope.
Recruiting as many Champions as posssible...

The pic doesn't include the 3 with my Sovereign (2 Channelers and a close combat specialist) and a few that I recruited some turns later.
I consider vital those with Food and Tech bonus. Gildar ones are also nice (go Janusk, go!). Combat Champions with Crushing Blow are the most interesting ones if you plan to use them in non-magical combat.