Think I need to Clarify What I originally suggested was that streamer be able to automatically construct and incert the unicast stream URLSimply becuse doing so manually is a burdensome task, riddled with the posibility for the user to make an error.
ie, not only does the user need to know the syntext for correctly constructing unicast URL
But,, they also have to know/find there numeric IP-address & Streamer-ID
(
both of these being lenghty complex numeric values 
Ok, once they have obtained the knoledge, its possible to copy/paste everything over
in order to construct the URL
But as the software already has ALL this information & the auther knows the correct syntext
Wouldnt it be much easier (especially for an inexperienced user)
if as a default unicast setting, was to automatically construct & incert the unicast URL
And that:
There be a switch to overide/disable "auto'construct"ion
So that more experienced users are able to manually incert an alternative, should they wish to do so !
Its that simple.. ... ... PS:
I also agree with the off-tread poster's,
it would be a nice option to be able to define the maxium number of listener's
would save doing the maths
off course one has to remember to allow for overheads/excursion to higher levels
especially if broadcasting using Ogg-Vorbis
which is why I asume Iain took the define by bandwidth root 
thou like I say, thou related, this is off'topic, .. hence off tread