Ahh yes. Our team had something exactly like this. It was a cascading lift. It was in Billfred's second link on the left. What we did is we took 3 pipes and they cascaded. We used a CIM motor and the kop parts gearbox. Now it looks like you dont quite know what FIRST is. So here, you could by a CIM motor from <
http://www.ifirobotics.com/first-store.shtml > its part number < FR801-001 >. Now buy gearing for a reduction of about 20:1 or 30:1. I recomend 3 stages. 2 through gearing and 1 through chain and sprocket. Now what we did is we went to a local sailing shop and bought sailboat pulleys and a white rope. They were both rated for 1500+ pounds. We took off the outer coating which is just for protection. We had 3 tubes that fit snuggly inside each other. I'm guessing you would want to use 3 tubes that are each 3 meters long and the one on the bottom being 2.5 meters. We used a mill to key each tube for the ropes to run. We drilled holes in the pipe near the edge and used a 1/8" stainless steel rod. We mounted the pulleys and tied the rope. Finally we welded it to 1/4" Aluminum disc and then hooked it all up to a 2.5" od spindle. The spindle was then hooked up to the cim with the gearing. I think ours was 27.16 to 1. I dont know much about the electrical part so someone else can help you there.