Nearly 1500 C42 Ikarus have been built in this category and with an empty weight of 279 kg and two 86 kg guys on board it has fuel for a couple of hours. It is not the prettiest of aircraft but it gets the job done. Genghis is right there are a lot of high performance machines which are effectively single seaters. I am not sure I am comfortable with some blanket decision that ultralights have to carry two people or should only be flown short distances. The idea is to make things simple, safe and unbureaucratic, sadly not easy in aviation. If the rules stop you adding equipment that makes you safer that does not make sense.