I did a search for the type of plugin you are looking for.

I was able to find two different options that I think will work for you!
Pinpoint Booking System is in the plugin directory and can be downloaded for free.
and
WP Booking Calendar
This one you would need to purchase.

I hope that this helps you with your inventory!

Let me know if there is anything else that you need!

Best of Luck!

~Josh