To be honest mate, mporn was ok, mobileporn went recently I believe which I personally, would have preferred. If you can make a brand out of them and you want to pay that much, then its down to you chap, but there are thousands of sms / 3g / mobile / mms / pda names still available that have expired
15 bucks a pop from directnic.com
You know the boom of e-commerce, everything was "e" orientated for a while .. fucking yuppies running around Islington screaming "I am an e-commerce expert" lol I know a lot of people that got burned with that.
Now microsoft has moblogs, moblogging is big as is phlogging .. "phone blogging" .. podcast was thought to be the new thing and its very rapidly dying a death in favour of microcasting.
3g is going to be around for a long time, before 4g comes into fruition in 2012 or thereabouts ..
http://www.3g.co.uk/3GWorld.htm /
http://www.blogs3g.com
So me personally, I wouldn't pay 4k for anything m"insert name", I like the
3g/sms and mobile names 
Nick is gonna shit, he loves mobiles lol