Most modern trams offer that, essentially it's because most modern trams are continental European designs and having a forward view is commonplace on many types of rolling stock designed for those markets.
Most trams that I have ridden on have a glass or perspex 'wall' behind the driver that allows a good forward view, which is similar to a cab ride. I thourghly enjoy standing behind the driver and observing what they are doing. I did take a video once on the NET system between the Old Market Square and Bulwell, Its knocking around youtube somewhere when i can get back on my account I'll post a link.
Would be very hard to fit more than one person in the cab of a Tyne and Wear Metrocar! There are quite a few (ppor quality) videos of the system from the front seat on You Tube, although there is an official video which is available to buy on eBay and other sites which is much better. Or, you could pay the £4 odd to ride on it all you want for a day.