A few thoughts from someone who has helped advertise for large scale events and helped various organizations/conventions increase attendance:
1) There must be coordination on a grand level, this is absolutely true.
With tons of small mini bombs by tons of people and without much coordination, the money will still add up, but it won't necessarily warrant mass media attention or allow us to look organized. Sure, that may mean some people can't take the front seat, but that doesn't really matter when we're talking about the big picture.
2) Spread out the Money Bombs
This will give people time to save up money, advertise, etc.
3) Plan Events Around "Pay Days"
Preferably not at the first of the month (rent). When people get paid, they like to spend. Capitalize on this.
It's tough to plan mass events like what the Grassroots are trying to do for Ron Paul without some centralized point or individual who can say in which direction the movement should be heading. Everyone has an idea of what to do, it's getting all that stuff compiled while still working with Ron Paul's staff to maximize the efforts. Having set-in-stone dates for the Money Bombs (I love the quarterly idea someone proposed) will give the people time to plan and even let Ron Paul know when he can plan to do certain things that could further maximize the event.
I think doing advertising on a local scale and on the internet is doing us a lot of good. Maybe it's time someone started an "official" thread for a money bomb and put some of these ideas to a vote here on the forums. I guess the next step would be to do some outreach to some of the other groups who don't come here as often to get them on board. Then, we all do our best to stick to them and promote the events that we have agreed on while still operating on a local level as we have been doing but incorporate the bigger events into that localized message.
Just my 2 cents.