to answer your actual question, I've had pretty good success with the Pars brand. Despite what others are saying, I've been able to get the most amazing tahdig more consistently in the rice cooker. Here's an Amazon link:

http://www.amazon.com/PARS-Automatic-Persian-Rice-Cooker/dp/B00E7HUWOG

And here's a blog discussing the technique

http://www.mypersiankitchen.com/persian-rice-cooking-method-with-rice-cooker/

These rice cookers automatically go into a "keep warm" mode after the rice is cooked. The longer you leave it, the thicker the tahdig gets.

PS Don't forget to wash your rice, or have your oppressed woman do it.

PPS the rice cookers might also go by the Crispa brand name.