First thanks for the mod, love the idea :)

How hard would it be to add some more ranks to the list?

maybe some at 2500 kills, 10.000 kills, 25.000 kills and 100.000 kills.

Not hard but the overlays would get a bit much.
I was thinking of setting were you can scale them with a rank multiplier and buff modifier.
How about that with one more rank like general that buffs to mad level with a healing factor. But maybe onmy allow one general at any given time?

Hi, for me I would like to more ranks too. But don't go to mad upgrades. Better like 10% per rank. (2x range give you 4x more coverage + other bonus for DPS is good enough). For overlay: use other color for current ranks.
[For mime play style the best is bonus for range to counter masses of hard aliens. Other buffs make it overpowered even more.]

Adding general and option to alter how many kills to get rank and another to change buffs. Can leave as default or adjust to suit your preferences. Need to do a couple of other things and move house will publish next few days

Awesome, thank you. And good luck with moving.

I had a thought along these lines, there is a mod for Supreme Commander Forged Alliance called Total Veterancy, it employs a leveling system that is unlimited and automatically scales. Not sure if it's any use but maybe their code could help

entities need to be created at startup so will always be a cap, could be some ways about it saying you want x ranks to be generated but when do you stop?

If you use alternate forces with extra modifiers, ranks can get pretty crazy. 9 additional ranks + 9 additional forces provides 100 potential ranks.