For those of us that can't order from McMaster, I found another source for white nylon spacers:
http://stores.ebay.co.uk/naoutletI just received my order, and they are nicely bagged, and the shipping took about a week from the UK to Canada. Inventables sells them too, but not in a large variety of M5 compatible lengths. Also, these ones seem to have a larger OD which should make them a bit stiffer than the smaller OD ones I've bought before.