I use a 1K digital ballast and it runs about half as hot as my cable box, and is about a 3rd of the weight as my magnetic grow tech ballasts. Also the 1K digital is a wall mount unit so I just pop it on the wall and presto. It is swhichable meaning I can use both MH and HPS, don't have to push any buttons or anything like that just screw in the other bulb and it is ready to go.
I also use a cab like the Jam man, one for veg/mother and the other for flower. With that 1500 pounds you have you could put two cabs together as well. Also, go with the HID's if you are looking for quantity over a QP every few months on a consistent basis. The only problem I could see you having is heat when being a renter, because you can't do allot of venting out of the house and what not, but you can get creative enough to make it work, and there are always AC units.
Adieu