newpsdfromclip.jsx

// units setup, doesn't matter eventually
var originalUnit = preferences.rulerUnits;
preferences.rulerUnits = Units.PIXELS;
// create a new document (size doesn't matter)
var docRef = app.documents.add(128, 128);
// get the current layer (background)
var topLayer = app.activeDocument.layers[0];
app.activeDocument.activeLayer = topLayer;
// rename/unlock it as it is locked by default
app.activeDocument.activeLayer.name = 'Unlocked';

try {
    // paste from the clipboard
    docRef.paste();
    // delete the background layer
    topLayer.remove();
    // reveal the entire document
    docRef.revealAll();
    {
        // fit to screen snippet from http://forums.adobe.com/thread/980700
        var id57 = charIDToTypeID("slct");
        var desc15 = new ActionDescriptor();
        var id58 = charIDToTypeID("null");
        var ref6 = new ActionReference();
        var id59 = charIDToTypeID("Mn  ");
        var id60 = charIDToTypeID("MnIt");
        var id61 = charIDToTypeID("FtOn");
        ref6.putEnumerated(id59, id60, id61);
        desc15.putReference(id58, ref6);
        executeAction(id57, desc15, DialogModes.NO);
    }
} catch (e) {
    alert("Clipboard is either empty or doesn't contain a valid image.\nThe document will close.\n\n");
    docRef.close(SaveOptions.DONOTSAVECHANGES);
}

// restore original ruler unit setting
app.preferences.rulerUnits = originalUnit;