You can get Andy White's 144bcd track chainrings (he of fyxomatosis), which are made by an Aussie outfit. Generally I wouldn't recommend replacing the crankarms unless they show cracks or bends, or the threading is stripped. Maybe a new BB if yours has seen better days.

otherwise, the only thing I can think of is a good strap setup. riding with straps tight enough lets you really focus on making your stroke circular, which is better for you physiologically, and you can extract more power out of your pedal stroke.