I have this. http://www.amazon.co.uk/gp/product/B00B8NETGE/ref=noref?ie=UTF8&psc=1&s=kitchen Works really well.
There's a tiny little Coghlans version kicking about, I nearly bought a few in Canada a few years ago and then never bothered.
The Esbit one works pretty well ...
[video=youtube;zCurMiSsjsw]http://www.youtube.com/watch?v=zCurMiSsjsw[/video]
Good price at SportsDirect at the mo ..
http://www.sportsdirect.com/esbit-stainless-steel-coffee-maker-780035
Looks pretty good Rich, but that fella in the video well his coffee... I've emptied darker looking urine from catheter bags than his brew
Lets not forget the humble Ibrik/Briki combined with Turkish/Greek grind coffee. Cheap as chips on ebay.
I was yesterday thinking of picking up one of them but it looked a bit bulky, I might just pick one up later though.
I think he might have brewed up too quickly in that vid, apparently they work much better on a low slow heat