DJ Nik...
I too have been broadcasting on the internet for the last four years and have never experienced issues like you are, then again, I do only broadcast 2 streams - one at 96kbps and one at 128kbps, then again, I am using a dedicated server.. if you're being hit, it could be that you're getting everyone to connect directly - which is going to really bomb your bandwidth.. there are plenty of alternatives out there that, for the sake of preserving bandwidth, are a lot better... my host provides me with a 'slot' and depending on how much I pay each month, I can have the low plan option of 10 listeners @ 128 for £2 a month or pick one of the higher up plans for a tenner...
PM me if you wish to talk about this further
In the meantime, I live in a glorious area with very few on VM (most are on BT...) and I'm loving it.. rarely throttled and that makes me smile so hard my face hurts
My partner and I are both on the internet a fair bit (gaming and whotnot) and... whatever we're doing, we're doing it right! (we even have the stm thing sussed too... any game thats a gig or more, you download the first 500mb between 3-4pm and the rest after 9pm
)