1. Get rid of all that extra foam: Most people that pack equipment in a travel case are either using a factory pluck foam kit, or a design that subscribes to the old adage of 2 inches of foam around everything. In many cases, using custom cases with partitions and/or separators will allow you to use a smaller, lighter case and thereby help you make the weight limit.
2. Consider using a small graphics style case: Many people are using commercial shipping cases for airline travel. With an intelligent, custom case interior design, you may be able to shed 10-15lbs of case weight, and be able to carry the same payload. For instance, a particular buckle-strap graphics case measures 24x24x10 and weighs 14lbs. It will hold roughly the same amount of equipment as a Pelican 1650 case that weighs 24lbs.
3. Re-think the corrugated box: For extreme weigh-loss possibilities, you could keep a supply of double wall corrugated boxes, and employ a re-usable high-density foam/plastic cushioning set (not crumbly Styrofoam). As the boxes degrade, they can be replaced from stock, and the foam set can be moved from box to box. This is also a low-cost strategy, but it is not without a hassle factor. With the potential cost savings, it may well be worth it.
4. Get rid of that wood road case: Many folks in the music or broadcast business love their wood roadie cases. As a rule of thumb, anything small enough to check through on an airline can be put in a molded plastic case, saving you a lot of unnecessary weight and keeping the same protection.
5. Try using removable/alternate trays: Traveling salespeople bring their entire product line on every trip, even if certain items will not be needed for that trip. With a system of removable trays, you can customize case contents for each type of trip, and not have to bring everything all the time. You may then be able to get by with a smaller case.