Pressing the clock icon under the newest post takes you straight to it also. (If you are using condensed view, the clock icon is next to the new post)
Also, if there are more than 1 unread comments in the topic, they are separated from the read ones with a thick blue line.
Furthermore, apparently streams can be shared ( one I am using now is http://magicduel.invisionzone.com/discover/22/ ), made default (press the small tick icon next to its title; that changes the Unread Posts button to the stream you ticked) and accessed directly via bookmarks and they are found under My Activity