I am looking to develop an extension to OpenCart which will allow me to both sell products and sell scheduled services.

For the scheduled services, I would like to have the storefront interface change so the customer sees a calendar. It would be Nirvana for the calendar to show only available dates/times, but at the very least they should see a calendar.

Then, on the administrative side, there should be a place where there is a list of desired dates/times for scheduled services.

I'm wondering if anyone is aware of community-developed extensions which do this, or come close?

If not, any recommendations for how to accomplish this properly are welcome.

Thanks in advance.