On the mobile site, could the Talk | Active | I'm on | Watching | Search bar please be repeated at the end of each thread, like it is on the main site? I have threads set to show all posts as default and it's annoying to have to scroll aaaaaaaaall the way back to the top after reading a monster thread.
There is a back to top button ("Top" with a little arrow) below every post. If you're on an iPhone, you can also tap the status bar to scroll to the top of any page (this works in most apps, not just webpages). Does that help at all?