Recently, I have come accross these lovely crafted fixed gear hubs sporting a bolt-on cog system. Certainly, there is nothing particularly new about them. The idea of using a modified disc-mount front hub as rear fixed gear hub has been around for some time. Likewise, Level has been manufacturing this tasty bolt-on fixed gear hub for a while. What I like about these new hubs is that they are probably the best hubs you can get for a conversion. It has to be admitted that the person behind this venture (who I incidentally do not have the pleasure to know) has thought hard and long about what he wanted to achieve: a fixed gear rear hub capable of taking any chainline you can throw at it. If you are doing a conversion, forget about measuring the chainline, replacing BB, or even having to source another crank: this hub will sort you out at once. Rear axle spacing: sorted with lots of different spacers to fit track, road and MTB frames and have your hub centered nicely. Chainline not perfect: no problem either! just add some washers in between the cog and the disc-mount and you can fine-adjust it down to the mm. So, even if its retail price is just around 20 quid shy of what would cost you a proper track rear hub, it may well end up saving you even more money as, apart from re-building the rear wheel again, that will probably be the only thing you will have to buy for having your conversion up and running in no time.
Although I am sticking to my traditional threaded fixed gear hub for the foreseeable future, I will like to say "well done, mate" and best luck with your venture.