Mine grows fairly fast more out than up about a 1/4" and a few new leaves every week. I use a 18" florescent grow bulb in addition to everything else and it seems to keep my ficus healthy and growing. It also gets quite a bit of water from the dripper system and mistings. I use ficus benjamina, ficus elastica, schefferella, croton and pothos in my guy's cage.
Hibiscus will grow at insane rates after a pruning. They love being cut :\ My plants were a good 20" when I pruned them down to about 4" of wood and they just EXPLODED growth...one had a good 8" of growth in one week. I had to pinch them back and reprune the tallest branches. They will bush out more if they have better light- less light makes them way too tall and gangly and you have to pinch leaf buds.
Basically, provide lots of good light and prune the heck out of the plant if you want a lot of fast new growth.
Use a very sharp pair of shears (and sterilize them between cuts, especially on dead wood) and clip a branch basically where you want it about an inch above a node. These sites explain it more.