It would help quite a bit if we knew what sort of car you’re looking for (besides having a manual.) Most mfgrs. sell at least some of their models with manuals, especially inexpensive economy cars and sporty cars. Your current car, a JCW Mini kind of combines the two. If you want another moderately priced, but still sporty car from Japan or the US your options are limited. One obvious choice (or two, but they are about as close to identical as two cars can be are the Subaru BRZ and Scion FR-S. They aren’t very powerful or quick, but handle well and look the part. Because they are being sold as sporty cars and don’t have gobs of power, I suspect manual versions should be fairly easy to find.
The Hyundai Veloster is another Asian possibility, though it’s only sporty in looks. If you want more power and handling and don’t mind loud and rough to go with it, the Mazdspeed3 is a pricier option. Much beloved of younger drivers so don’t buy a used one on a dare. If you aren’t that young you might make some interesting new friends. Maybe that works for you. Buy yellow if you’re that person.
Or just get a regular Mazda3 if you’re saner and/or cheaper. Finding a manual may be a little tougher, but it’s an excellent little car and has nicer styling inside and out for 2014 (not changed all that much mechanically, except you can get the 2.5l version of the SkyActiv engine in the higher trim models. Not really essential, but the gas mileage doesn’t drop off much, either, despite the increased power. Otherwise I recommend checking out your local dealers online. Some put their inventories online, though I’m not confident they’re always up to date. If nothing else it can give you a general idea of how many manuals they’re likely to have.