For late fourteenth century "hidey-harness" I have one word: Lentner.
From a post on MyArmoury:
The Charles VI garment is seven layers of material with two layers of raw cotton (aka cotton wool) as stuffing. From the inside to the outside it is stacke[d] like this:
2 layers of linen
1 layer of raw cotton
2 layers of linen
1 layer of raw cotton
2 layers of linen
1 layer of silk brocade
_________________
James Barker
Archer for Lord Grey of Codnor
http://www.lordgreys.org/
That would certainly seem to give some helpful hints on how to build a protective torso portion. Lentners in period illustration all seem to have a lot of volume and body. We have more pics around than just Herr Ritter Walter von Hohenklingen -- though his effigy is really good for the buttons!
For pattern, you could do worse than Chapter 25 of TOMAR. It has a Lentner, gigantic bagpipe sleeve and all, on the pages just after the CdB. This garment is rather loose for incorporating hard kidney plates in it, but a form-fitting kidney protection would hide very well, as will low-pro shoulders, arms, and elbows.
Period Patterns 101 has it too, though PP often needs a grain of salt. Probably a bagpipe sleeve added to View I.
Two shots of Hugh Knight:
http://www.livinghistorylibrary.org/for ... si&img=226
http://www.livinghistorylibrary.org/for ... si&img=227
