This is an edit of: http://www.libtronics.com/2013/10/determining-if-device-is-tablet-on.html that can be used to check whether an appcelerator Titanium app should be rendered with a tablet layout.

titanium_tablet_check.js

function isTablet(){
  if(!Ti.Android){
    return Ti.Platform.osname === 'ipad';
  }

  // http://www.libtronics.com/2013/10/determining-if-device-is-tablet-on.html
  var height = Ti.Platform.displayCaps.platformHeight;
  var width = Ti.Platform.displayCaps.platformWidth;
  if (height < width){
    var w_inch = height /  Ti.Platform.displayCaps.xdpi;
    var h_inch = width /  Ti.Platform.displayCaps.ydpi;
  }else{
    var w_inch = width /  Ti.Platform.displayCaps.xdpi;
    var h_inch = height /  Ti.Platform.displayCaps.ydpi;
  }
  var disp_size = Math.sqrt(w_inch*w_inch+h_inch*h_inch);
   
  // Ti.API.info('Width: '+width+', Height: '+height+', size: '+disp_size);
  // Ti.API.info('w_inch: '+w_inch+', h_inch: '+h_inch);

  // The Samsung Galaxy Tablet 1 in our office has a disp_size of: 6.77 and renders titanium apps with tablet layouts nicely
  return (disp_size > 6.75);
}

Ah-ha, just found out that this isn't even neccessary, refer:
http://docs.appcelerator.com/titanium/3.0/#!/api/Alloy-property-isTablet
https://github.com/appcelerator/alloy/blob/7ca0be6f142046f328b6b911b28fa3117501e14d/Alloy/lib/alloy.js#L449