I want to make a replacement for heavy cream. I'm considering almond milk blended with a fat. I have a high powered blender on the way for this purpose (yes, it will blend).  Some fats I'm considering:   Coconut Oil  Butter Tallow (wet rendered, pretty neutral in flavor)   Blending the almond milk and fat together, is it possible to create a reasonably stable suspension with a consistency similar to cream this way?   Will the fat invevitably separate after a few hours?  Do I need to add an emulsifier or other ingredient? 
I have made what I call a mousse using full fat/lite coconut milk or unsweetened almond milk with the same results. I have always added chocolate (a mix of unsweetened cocoa powder and solid). I've not tried it without adding the chocolate component but have eaten it on its own and as a topping. It keeps for a few days in the fridge.   14 oz can full fat or lite coconut milk, or 2 cups unsweetened almond milk, divided; 1/4 cup or 1 oz solid dark chocolate; 2 T cocoa powder;  1/8-1/4 c. granulated sugar of your choice;  1 packet or .25 oz unflavoured gelatine;  1 large egg separated;  Refrigerate coconut milk over night. Open and take out the solid stuff on the top and put in a pot. Put the left over liquid in a bowl and sprinkle gelatine over it and let sit to the side.  (If using almond or lite coconut milk, put half in a pot and sprinkle gelatine over remaining cup).  In the pot add chips, cocoa powder and sugar to milk. Bring to a slow boil stirring it constantly until chips are melted. Separate egg ad put yolk in bowl. Whisk yolk while slowly pouring hot chocolate mix into it. Once incorporated pour back into the pot. Whisk slowly,  but well,  while bringing it back to a slow boil. When it thickens, add to gelatine mix and whisk until completely incorporated. Put in fridge until it sets.  When it is, whip the egg white to stiff peaks and fold into pudding. Cover and put back into fridge until ready to serve.   I usually eat it by itself with toasted shredded unsweetened coconut and/or toasted nuts. It can be used as a pie filling or as a whipped topping alternative. I've not tried piping it. There is a commercial stabilizer called  Dr. Oetker Whip It! that might help give it more structure for piping.  