Lets just clear this up for the OP - for me a basic bulker shake mix consists of the following genaral ingredients - powdered oats/ whey/ natural peatut butter/ cream/ eggs/ whole milk/ fruit
Hell - if you want 2500 cals just keep adding shit.
However, realistically - I cannot see the benefit of a 2500 cal shake. The most I would have is 1000 cals. you can always blend up a big batch, have a shake and then take the rest to school for later in a protein shaker.