Some people perform Salaat with 'bermuda' style pants or wit shorts which cover the knees.

Answer

It is most disrespectful to perform Salaat with shorts even if the knees are covered. Bermuda pants are a haraam kuffaar style. It is therefore haraam to perform Salaat with kufr style. It is not permissible. Those who perform Salaat in this lewd fashion have no respect for Allah Ta'ala. When one performs Salaat, one is in the Presence of Allah Ta'ala. It is necessary to be Islamically and respectfully dressed when standing in the Divine Presence to perform Salaat. Similalrly it is not permissible to be dressed with only a T-shirt and a pants during Salaat. Such Salaat has to be compulsorily repeated with descent Islamic dress.