Recently i started a project on developing an IDS for wireless ad hoc networks.
Major players in the security sector are way ahead of you. Take a look at ISS for just one example. There are many more.

And found that ad hoc networks will be the hackers' playground in the near future.
Really? How many businesses do you know of that actually allow this implementation? Based on regulatory compliance, no one will be able to do this in the near future. This leaves home users and businesses that don't have to comply. Even then, how many understand how to setup ad-hoc WiFi?

Inspite of all these weakness, i see lot of commercial applications such as bluetooth( lilttle variation from ad hoc) being implemented.
Now here is where I agree with you. Bluetooth (which I classify separately from traditional wireless) and RFID allow scary amounts of leakage at close range.

As a POC, I sat on the patio of a local coffee shop with a simple bluetooth directional antenna (built with internet instructions) and I was able to see *tons* of sensitive information.

--TH13