When I was in college, every semester, my schedule was different. This unfortunately meant that I ended up working for several different employers when I was in college. Almost all of them sent me to get urine drug test. It would have been easy as pie to smuggle in and mix the powdered pee if I had needed to (I didn't use mj much at the time). For all except for one place. One place, they gave you 60 seconds only to pee, once you went into the bathroom and closed the door. Talk about fucked up.

__________________
If you puke on me,
I will cover it in velvet and sequins
and sell it back to you. -- The Nixon Poems; 1972

And how would you get this powdered urine solution to acceptable temperature?? The only cheating setup I've seen that I'd try, is actual clean urine in a bag, wrapped with insulated nichrome wire, and an LM35 temperature sensing circuit, with a tube taped to the underside of the dick so the bag just needed to be squeezed.. My buddy actually rigged that up, but in the end he didn't even need to use it so I don't even know if it would be a sure thing.. He was worried that the plastic composition of the bag would be detectably different than the sample bottle..
And alot of tests have time limits..

I would suggest to go to the GNC store and buy creatine.Also drink lots and lots of water.