I built a new jig to measure the placement of the axles relative to the deck.
Knowing relative axle placement will be especially helpful when a company stops making your favorite deck shape. If the deck manufacturer puts more or less flat between the endmost truck mounting holes and the curve of the tail or nose, your trucks won't feel the same on that deck, and you might want to get trucks that move the axle closer to or further away from the curve of the tail and nose.
Without further ado, here is the chart of a bunch of trucks I have measured so far:
For now, have fun studying the chart, and please do ask questions in the comments section. Every question helps these measurements get more accurate and therefore making you a much more informed skater.