1. This is the limit of the standards, some manufacturers of the cable and Media convertors may claim extended distances but they would not be standards complient. You would need to check with their Techinal Support groups concerning the protocal you need.
2. As far as I know there is no standard fiber known as 5/125. The following fibers are the standards used today in glass, there are other sizes available in a plastic varity. Single mode fiber is either 8/125 or 9/125. Multimode fiber is available in 50/125 and 62.5/125.
Joseph Golan, RCDD