I found a really good solution for a running/sports armband for the 85xx series BB and wanted to share the info.
There are not any currently available on the market which are made specifically for this model/series. I expect that may change in the future but, right now, there are none available.
Fortunately, this device is very similar in size to an iPod Touch. Generally speaking, its the same exact package - only a little (<1/4") thicker.
That said, most any iPod Touch case will work. Most have complete plastic covers for the screen area.
A better solution is from a company called Griffin, in their case series called Immerse. Griffin Technology: Solutions for iPhone
I didn't see this model on their website but I found it al Walmart for under $10.
It's a nice velcro strap with a couple small reflector patches (for safety when running at night). The phone holder itself is rubber and has no plastic cover. The 85xx keyboard is fully accessible. I had to add a hole for the earphones (which includes microphone etc). All in all I'm quite happy with it.