Requirements
First, you need to have some software to be able to do this. You only need 1 program, personally I use:
-> Hex Workshop (for itemcache.wdb editing) - Download it here: BreakPoint Software, Inc. - Downloads
Next, you need to be able to look up the model id codes in hexadecimal that again has the digits swapped.
To make this procedure easier I made a website where I used Wowhead layout code and search engine, so the site is depended
on accessing Wowhead (if they are on maintaince, then the site will be on maintaince too :P) - but anyway
let's go on with the tutorial.
Step-by-step
This is the unique part, depending on what you are changing. First you need to find 2 items.A.1.0) Go to your WoW installation dir and enter the WDB folder (example: C:\Games\World of Warcraft\Cache\WDB\enGB)
A.2.0) Make a backup of "itemcache.wdb" by copy-pasting it (just in case).
A.3.0) Right-click and open "itemcache.wdb" (not the backup ofc) with Hex Workshop.
Item #1 that you will change model to look like Item #2, so let's begin.
As an example, I want to make Fool's Bane - Items - World of Warcraft to look like Thunderfury, Blessed Blade of the Windseeker - Items - World of Warcraft (classic example)!B.1.0) Look up on Wowhead.com for the items, looks (screenshots) and such for two items you like.
B.2.0) Open them both on this page: Item Parsing
Let's move on, we got our itemcache.wdb ready codes for our 2 items.B.2.1) I will open two pages on Item Parsing , one that shows the Fool's Bane and other with Thunderfury.
B.2.2) Now write down their "Itemcache.wdb" numbers somewhere (notepad, paper, your choise).
B.2.3) For these items Fool's Bane is "17af" and Thunderfury is "8e77".
Remember that you won't see the model change on the character screen, only when you enter the game.B.3.0) Bring the Hex Workshop window in-front now.
B.4.0) Push the Ctrl+F keystroke.
B.5.0) Search for "Fool's Bane".
B.5.1) Look at the bottom right box, you should see 4 entries. Click the one on the bottom.
B.5.2) NB! If you have not seen the item in-game, it won't show on this list! Then you can't do anything about it. :P
B.6.0) Look at the top-left box, with all the code (whoa!)
B.6.1) You should see the text Fool's Bane now marked on both the right side box with normal readable text and the main code box.
B.6.2) After the marked code there are allways "00" (as a space, so the program knows where the item title ends).
B.6.3) The following 4 chars are the model id in hexadecimal swapped around! :P Take a look on your note, you can see the "17AF" code written down on your paper/notepad.
B.6.4) I guess you allready know by now what we are going to do here, simply mark the 4 chars and manually type over them with the Thunderfury code!
B.6.5) Final results should be, you replacing 17AF with 8E77.
B.7.0) Save the file by using the Ctrl+S keystroke. Do a new backup if it asks, just to be extra safe.
This method is quite secure, so it's definietly safer than running the model edit fix program for small
things like this!
Visual guiding
Made screenshots, step by step how you should do this example edit.
When you are doing other edits you simply look for other chars to edit,
procedure remains the same.
Final words
Good luck editing your armor and weapons, hopefully the website and tutorial
will help you to do the changing more efficiently. Have fun!