They actually add to your trade good count in the info tab? I know equipment gets counted as cargo, and thus crates, if you have more of it than your troops can actually wear.
Yes, the eyecandy script lists them as trade goods. I was moving just fine without any crates/extra gear, but when I bought goods (which, with the "gear goods" brought my goods total to over my number of troops/horses) I noticed a dramatic loss of speed.
I may be wrong, I don't know. For exact numbers I have:
1000 trade goods
1562 men
1500 of each armor type (640 of my Norman Mail Chausses aren't displaying as armor, but as goods)
720 horses (50 more Barded Warhorses are considered "goods")
595 Polearms
500 1h (50 more Spathovaklions are considered goods)
500 2h
515 shields
150 Bows
150 Crossbows
350 Arrows
350 Bolts
410 Throwing (30 Cavalry Spikes displaying as goods)
If I'm assuming that throwing/ammo count as 1/2 of an item (I've heard different things, but most seem to think 1/4 or 1/3), I still only have enough weaponry for each man to be well equipped (two weapons) @ 1482 men, so I'm even a bit under what I could be carrying in terms of weaponry.
770 total items which are counted as "goods" with the eye-candy script. I thought that as long as I had more men than any individual type of good that the effect wouldn't be so profound and that I'd be at around 20-25 movement instead of the 12-13 I'm at now. My only guess is, since it's not that I have extra armor/weaponry, that these things are actually being counted as trade goods for whatever reason.
I should note that on the sidebar of the Info screen in, with the eye candy script both enabled and disabled, it lists my goods at 1000 even. It's only in the sorted inventory numbers for all armors, weapons, goods, et cetera where it shows my trading goods at being higher than they actually are.