I've toyed with an MS Excel spreadsheet, which sort-of works. I'm not that good with Excel, or math.. but it's available if you want to try it. Basically it's something I made to help me with armours until someone does create a comprehensive calculator.
I've grouped wearables into bone/studded (16 base resist), other armours/helms (15 base), and hats/masks (24 base). You enter values in the boxes in column B, and refer to the appropriate total at the bottom for the unravel point value. It's very quick-and-dirty coding, and ugly to look at, but it seems to work. I think I worked out the resist score right; I did it the long way before and got the same results by hacking the figures around to as it now stands.
Two properties I'm not sure of how to rate their intensity, Durability and Lower Requirements, as they range from 10-100, not 0-100. I'm assuming 10% intensity = 10 unravelling points. I didn't sweat these two so much as an approximate figure is a good enough guide for my own purposes.
I haven't included shields as they're quicker to estimate at a glance than type in, and I'm not touching on weapons, waiting for someone clever to do that. I may try jewels next as I have a stack of those to sort after I'm done with armour.
Such that it is, here's the spreadsheet:
Armour_Intensities.xls