Just a crazy suggestion here....
Get an Apple TV and a small portable WiFi router.
Connect Apple TV to the projector (you might need an HDMI to VGA adapter)
Get a small, portable WiFi Router
Download the Remote App for your iPad and stream wireless from the iPad to the Apple TV.
This is basically the set-up I am running in my house - No wires except between the Apple TV and the projector (or in my case my Plasma TV). This works flawlessly....as a bonus you can connect the Apple TV to the iTunes library on your MacBook (if you happen to have it along) and stream just about anything to the Apple TV.
You could buy just about ANY wireless N router...so between the Apple TV, router and an HDMI adapter you would have less than $200 invested.
If you get a new projector it probably has HDMI inputs.