We definitely have heard a large number of our community members ask for rails and more grind-friendly environments. We've passed along that feedback to our development team, but at this time we have no information to share regarding its addition to the game. If that information becomes available, the community will be the first to know via our social channels and here in the forums.
You can already slide and grind over everything you should be able to, and with a decently working mechanic, too, but the opportunities are pretty rare, sadly.
For info and vid, check here: http://forums.ubi.com/showthread.php...1#post12098212