Adding Sleeper Windows to a Volvo VNL610/660
Over the past few years a number of forum members have added windows to the sleeper area of their VNL610's/660's for various reasons including added ventilation, to cut back on the claustrophobic feeling that some people tend to get in a confined space and to enable passengers that travel for hours on end on an aftermarket Jack Knife Sofa to observe the birds, the bees and other scenery that passes by on extended trips.
Here's is a series of photos of a window installation details what's involved in a project like this.
It should be noted that if you install windows that are around 14" or taller in height that you will have to cut out and relocate two of the cab side wall stiffeners to a lower position on the wall as indicated in several of the pictures.
Hogrydr (Jim) elected to install shorter windows in his truck therefore he was able to avoid the additional work involved in moving the side wall stiffeners during his window installation.
In my opioion if you intend to have your children or a friend or two accompany you on the majority of your trips you're probably be better served to install larger windows.
On a parting note, be forewarned that you will probably have to come up with your own solution for interior window trim as the sleeper walls are several inches thick on VNL610's/660's.
BTW, there are several recommendations in the thread above about fabricating your own window trim.