I would like to share with the script I wrote in Maxscript. RandomSelector is a tool for selecting the of levels of object: verts, edges, faces. It requires previous conversion to Editable Poly. Interface is pretty simple. "Random" button is a normal random selection from all the elements in object (Coin Flip). There is an other option of random selection under "Select" button. It randomly selects faces, edges, verts but after you can reduce or increase the amount of randomly selected elements. It can by done by pressing "+" and "-" buttons or throughouta slider "Amount:". Below see "HowTo" video.
Please report bugs and versions of 3ds max that you have run it on because it was written for 2010 version. I hope you will find it useful.You can download the script HERE.