I'm new to CoBM so just making my way through all the threads. I was told that it was already suggested that subdomains be created for each state so that one can keep up locally with what is being planned, doing, etc. Being linked with the main organization would allow those in states to cross reference events. So, having such an event as you're talking about would be possible if there were locals in each state that could coordinate to have a function on the same day but in their respective state. That's how I would approach it at least.
Having a charity is wonderful and it's definately needed now with the recent bill that passed. We're heading into an even deeper “recession” and people are going to need things like food and basic needs. I know in our area diapers, gas cards, and such are very much needed in the community. I know that a lot of churches do rummage sales. They are best done at the start of summer around May/June when kids are getting out of school but before vacation when people will be looking for things of that nature, and then done again in August/September/October when people are back in school and looking for school clothes, etc. Also, if you're looking at running a huge rummage sale the best way to handle clothing is to get paperbags from the grocery store (have people donate them or such) and then do a $5.00 anything in the bag. People love that sort of thing. You also want to make sure to have lots of “helpers” people with name badges and money aprons. This way you avoid long lines and people can check out. If you want just one checkout center you'll want to have 4-5 cashiers and one in and one out. This will help direct the flow of traffic. The use of long tables works well because you can create a box that people walk around but that there is only one way in and one way out. Helps avoid missing someone who hasn't paid for something, because these things can get crazy busy.
The other types of fundraising events that work well is bake sales or pie sales. A local church up here sells baked pies right before Thanksgiving and Christmas. They sell for about $5.00 per pie. Of course, you'd need to have a ton of people baking pies!
You can also do auctions. They work well, and they often can bring in a great deal of monies.
Now, if you simply want food drives you need to organize places to collect the foods. The best use of food drives, unless there is a place in each state who is willing to host a CoBM food shelf is to simply do baskets up for holidays. You can generally work with local school districts who will know which families need food for the holidays, and those are the times of years most appreciated for such things (not that all times aren't but those are the tougher times when parents are trying to buy gifts and food). Typical baskets generally include Turkey or Ham, sometimes both, the fixings for traditional meal like potatoes, stuffing, yams, pies, veggies, gravy (jar or canned), marshmellows (for the baked yams), rolls, cranberry sauce, etc.
Now, a place where I lived in Illinois did a great set up. They collected clothing throughout the year and then just before Christmas familes who had applied for help came to the church and were given one garbage bag (yard leaf size) per person in the household and were allowed to go through and pick out clothing and any items donated. They then were given a Christmas box, and a gift box. Generally toys are given with just ages written on the tag (so you wrap them and put the age on the gift tag with the sex of the child). It's a lot to organize and manage but it is very helpful for the community.
Anyhow, as I said I'm new. I'm up in Minnesota and would be more then happy to meet up with others in the area who want to do such things or at least start talking about them.
Oh, one more event, car washes!!! Everyone loves them and it gets your children involved as well.