With out question a double sided four leading shoe brake (4LS) is the coolest kit out there for a cafe racer hub.
There is a dual single leading shoe (SLS) one from a Benelli looks pretty cool. If you could get one for less than $500 it would be a good deal.
Available new is the Grimeca 230mm stopper. On the same hub as the Benelli but has different backing plates. available for about $700+ I have one of these on my SR500 and the only complaint I have is the weight. This is not for guys that like to wheelie! It will stop you fast though.
Also keep a look out for a Suzuki GT750 double sided drums (also called a 4ls brake) could be a good cheaper option for a good drum. Usually available for about $250 - $350. They're really good brakes for the money, but usually need to be restored. Like re-chroming the arms turning the liners and getting new shoes. could be spendy if you get a cheap crappy one. For that reason it can be worth it to look for one thats in really good shape. I have 2 of these in my collection: one is fully restored and the other is somewhat less attractive. :-)
There are other truly exotic (and sweet looking!) 4ls brakes available Ceriani and Fontana come to mind, If you have deep pockets these others are a good option, if not, they'll likely cost more than a complete project bike. Unless you are playing the "I'm better than you" game in the ARMHA paddocks these are a little over the top.
Another consideration is the displacement of your bike. I don't know if I'd want to have drum brakes on a bike bigger than a 650cc. If you are doing a 750 or larger discs would be a sound idea. (or life insurance.)