After all the time that has passed, I don't know if anyone actually has any use for this but...
While I was trying to build the perfect tripped out skell in the least amount of time possible, I started exploring the Skell weapon id values in attempt to find the parts I was looking for with the highest level, highest serial number, and an XX rank. After all the notes I took and the number of values I searched to find everything, I decided to compile a list of all of the Skell Weapon IDs and what they correspond to. Just as a way to thank the people who made this tool and to contribute something, if only a little. They are sorted both by ID value and broken up into the relevant Skell sections:
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(that's a pastebin extension, site is freaking out on me if I post the full link)
1.) Follow the standard procedure in XCXGecko for editing a skell weapon (Do it on the weapon you will "sacrifice")
2.) Replace the first 4 values in the weapon's code (Ex: 1C21C009 016F5640 00000940 050016B0 89900000 00000000)
3.) Go down/up one weapon then go back to the modded weapon
4.) With the weapon changed, immediately equip it (The game tends to purge the weapon into the either otherwise)
5.) Once equipped, it is now locked into your inventory and can be removed safely without the weapon being purged
The range of values covers all the variations of that particular type of weapon. Which means the different equipment level versions, the serial ids (120, 130, 140, etc.), and the rank. I just labeled them after the name of the first variation to appear in that range. The earlier values don't seem to have much order to them, but the XX rank is always near the end of the values. Also, each variation of a weapon covers about 7 different weapon IDs. You want to pick at the lower end of the values. The later values give a gimped version of the weapon which has no built-in augments or open augments slots.
For example, the Diskbomb Sidearm has a range of 0x10D8 - 0x1177. The best bet is to go for something like 0x1170, as it will give a value of the Diskbomb that is XX rank, top serial number, top level, and allows for augments. Whereas 0x1177 will give a gimped Diskbomb that is XX rank, top serial number, top level, and does NOT allow augments.
Also save before changing anything in-case you do something stupid. I dunno what happens if you mod, say, a back weapon into a sidearm slot and if the game will even let you equip it, I never tried. But its prob not a great idea.
It's not perfect and there may be some slight mistakes here or there, but poke around the ranges of what you want and you are sure to find it soon. If anyone actually uses this and notices any mistakes, let me know.