For options to include [in the mostlikely never coming next version] just look at
kisMAC. This tool is sooo much more mature then Netstumbler.
Netstumbler was fun, when it was released, it is fun for a first attempt for Wlan newbies but for todays demands it lacks more then it gives.
+ Editable Vendor file
+ Option for "quite mod"[listen only]
+ Channel selection
Cheers,
mokum