its been a while since I bought one but the older chessmaster platform allowed you to configure the engine and you could make it pretty human.
What you need to do really is be able to configure it so that it randomly picks from the top moves (say within .25 score of the best move), has a limited search depth (say 5 or 6 for 1600 or so level play??), book, database and mate-search are disabled. You may also like to have things like "treat draw as (win, loss)" options, piece value adjustment (bishop 3.5 vs knight 3.0 for example, or queen 8 or 8.5 or 9 or even 10 these things make huge differences).
Not sure which of the current ones have all these config options.... but that is what you are looking for.
In your openion which chess engine plays/thinks like humans,may not be the strongest.