You'll find at the end of the day it takes far more then 750K to get a Google feed. You'll also find it takes a multiple of that number over time to get a decent rate from them. By decent I mean enough that you'll earn more with your own feed then you would at say Domain Sponsor, Fabulous or any other google feed.
Assuming you have the traffic needed to "compete" then you need software to run it on. You're not going to find an off the shelf package to do this. It will surely need to be custom written. Besides the simple steps of this software like displaying a template with listings there is all the reporting needed and most of all a good/great fraud detection system in place. Without this you'll see the feed getting closed probably much quicker then expected. Don't foget you'll need hardware and bandwidth to run it on.
There is a whole lot more work involved in running a parking service then you would think. By the time you figure in hardware, software, bandwidth (co-location of machines), maintenance, backups you'll be lucky to get close to the earnings you see now at other services, plus you have you own time involvement.
I run search engines and parking sites so this isn't guessing on my part. It's a lot of work. BTW, I have both a Google feed and Yahoo/Overture feed as well as many smaller feeds and guess were most of my own domains get parked? DS, Skenzo, Fabulous, Parked, TrafficZ, GoldKey. I test them each of them (constantly) to see where they produce the most money. I have some that I run on my own feeds but less then 10%.
Now with all this said, don't think you can't do it. You can, but you really want to think about having more like 5 million and not 750K monthly uniques to make it worth the while.
Carlo
