Judging from how Metal Slug just came to the US VC a few weeks after it arrived in Europe, I'd say there could be a decent chance of Samurai Shodown hitting America pretty soon. But then there's always some peculiar things going on with the Virtual Console, like how everyone has Axelay (even Australia) except for Europe, so it's hard to predict with any great confidence.
For the record, the PAL Virtual Console is no bed of roses - slow gameplay and borders afflict most games to varying degrees (Mega Drive/Genesis most of all), the only exceptions being Turbografx, import games and the very occasional game that was converted well originally (e.g. the DKC games).