I'm trying to find anyone that has experience with creating and selling Joomla Components or extensions that they have added domain validation script too?

i.e.- Someone purchases your plugin, sends you there domain with purchase, you insert there domain into a validation component on your server which authorizes there site to use that sold component to its full functionality.

If so, what experience have you had with it? Has it been good or not worth it? What are some tips to having this built into a component by a freelancer?
If you paid for this to be done, how much and if your answering as a freelancer, how much would you charge to build something like this into a component?

Any insight would be very helpful. Thanks.

I've added a poll above to help me determine if this is a good way to protect my investments.
Would you purchase a really great functional component that has a single domain use (or bulk purchase) license(s)?

Have you started your project? Are you invested in joomla?

@jasondwolter, while I don't create or sell Joomla extensions, I've used plenty of them over the past few years, both commercial and non-commercial. I'm okay with paying a fee for an extension and having to provide the domain to receive a validation key, if that helps your decision