This might not be what you want to hear (buy new hardware!) but for this sort of application, the RN-42 works really well. It has this mode that's basically a drop-in replacement for serial cables. You can set it up using only jumpers. You can pair two modules, then remove the jumpers, and from then on they will auto-pair, all without needing any software configuration (until you reset them using another jumper.) The default baudrate is 115200, which in my experience has been fast enough to not require software reconfiguration. There is a 9600 Baud fallback jumper, but for other rates I think you need software configuration, which isn't persistent iirc.
I've used the module for several projects, for example to achieve galvanic isolation in an ECG project. It works well within the constraints of bluetooth (pairing gets a bid dodgy once signal quality drops, i.e. with distance, and it takes longer to connect if both modules aren't powered at the same time, probably because they eventually enter power saving mode if no partner can be found within a minute or so.)
In fact they're so useful that I built an adapter board that accepts both TTL and RS232 serial level I/O, as well as power from a standard lion battery, and keep them in my tools drawer just in case