The other problem with going the vintage Campy NR/SR crankset option is finding a triple bottom bracket. These use the thin cups, not the thick which are usually used for doubles. Not sure what you are intending on putting this on, but a spindle for English (68mm) just went on ebay for around $19, so they are out there.

If you don't care that much about period correctness, but still want Campy, take a look at their Racing-T triples (usually 52/42/30), which can be had fairly cheaply used (ebay, etc.). You will need the BB as well (Campy AC-H or the Centaur BBs will work for this, 111mm IIRC).