Since OPC 2.0.304 we are adding a new feature into OPC that supports additional address to be shown at the checkout which can be especially usefull for Telecommunication companies where customer's Bill To, Ship To and Installation Address is required. To enable the third address, mark your address fields within Shopper Fields tab at OnePage Checkout backend.
To ask for support for this feature you can check our forum post here or write us an email.
The printscreens are using clean_simple2 with joomla art's ja_mero template with VM2x. The feature is fully supported on VM3 as well.