We need to see the picture if possible.
If the picture has 3 tiers with separator bowls, and the customer wants 7, it might be impossible. There is a limit to how many tiers you should balance.
This is a safe and durable support system for the 7 tier cake. http://www.wilton.com/store/site/product.cfm?id=3E3143DE-475A-BAC0-52E8E24115E1EED0&fid=3E331070-475A-BAC0-59D1F5191FA0F3DB
You can add globes of any diameter that have holes drilled through the middles, to fit over the clear pillars. This would be a DIY add-on at a proper price...do your google homework.
OK I also looked at the Wilton globe separators. The 3" globes would have to be drilled out to slide over the pillars. If you have access to a drill press to do this straight, OK. If not, then don't buy them.