I'd like to change the storage capacity in colonies, either the standard 100 that it has from the start or the amount added by building and/or upgrading the warehouse gives. I've looked through all text files with no luck. Any suggestions?

Gameplay tips that involve wagon trains, extra colonies, and boats are unwanted, that's what I'm trying to get away from.

Your only hope...

http://www.freecol.org/

Well, you could *cheat*, but that doesn't actually fix your problem either. Basically you'd have to do some deep executable hacking.