I have hjust watched the 2005 movie Beowulf and Grendel which starred Gerard Butler, of "300" fame. He would be a good choice for Druss, but in my opinion better suited to the Wayander or Skilgannon characters, because he is tall, slim but well built and has already starred in at least 2 movies where swordplay is a factor. For Druss, you need somebody who is about 6ft tall, very well built, and he also has to age from the 17 year old wood cutter who married Rowena to the 60 something year old campaigner who held the battlements of Dros Delnoch against the invading Nadir hoards.
What about Hugh Jackman - he has proven that he can do the action guy thing, geez, what can't he do...,certainly accents. Wolverine, Van Helsling, and he is built...he could do young Druss to old Druss, no problem... God, can you pick the Aussie Gemmell fan?