Simon Scarrow's Eagles series seems to be a kind of Sharpe set during the time Rome is trying to conquer Britain. I've only read one (two more in the to-read pile), but it's decent historical/adventure fiction.

I haven't really checked around for prose historical fiction from Japan, but I've read a few manga here and there. The author of Kaze Hikaru (about the Shinsengumi) impresses me with the research (s)he puts in, and the historical notes on what was accurate and what wasn't.

XWA