Unisolar PVL 68

I am interested in these flexible panels to put on a flat roof for a new build house. Are they still available? Can substantial numbers of them be linked together?

Yes - they are still available, and they are ideal for houses. In fact that is what they were designed for! If using them in a residential situation you would usually link them together to a grid-tie inverter, in order to connect them into the national grid system. That way you can still use grid electricity at night and in the winter when you aren't getting much return from your solar panels; and in the summer you can sell your excess electricity back to the electricity companies.

You can link any number together, as long as your inverter is rated to take the power that they produce.