Hey there. I've also had issues with the item inspect panel being out of position. I know nothing about HUD editing, but decided to spend 5 minutes fiddling with the numbers to see what I could do, and I believe I've fixed it.
Here's a bunch of screenshots: http://imgur.com/a/Ou24I
"ControlName" "CItemModelPanel"
"fieldName" "itempanel"
"xpos" "0"
"ypos" "0"
"zpos" "10"
"wide" "290"
"tall" "100"
"visible" "0"
"bgcolor_override" "255 255 255 0"
"PaintBackgroundType" "0"
From yayahud/resource/ui/HudInspectPanel.res
If you make the grey box transparent it looks really nice, but you'll need to move the chat higher up as it covers a lot of the item info (which is already a problem with the current design). Example: http://i.imgur.com/Pc5LGpY.jpg
Like I said before, I know nothing about HUD editing, but this seems to work for me. It's pretty massive, because some item names are very long and have a lot of information to go with them. Anyway it's not like you'll be inspecting items mid-battle! I'll leave it up to you for further testing and tweaks :)