Now depending how much you want to stick with PJ's/GW's vision of Lord Of The Rings this may not be for you however there are some great miniatures currently up on Kickstarter that would do a fine job as Hobbits and Trolls, they're in the add ons section of the Dwarves at Arms campaign by Macrocosm Miniatures:
https://www.kickstarter.com/projects/20 ... es-at-arms
There's a wide range of various halflings available and the price for them is such that you'd be mad not to chip in for some just to see how they look.