I released AltSoftSerial today.
Basically, it's an alternative to SoftwareSerial, which uses a hardware timer to interfere much less with interrupts from other libraries. It is also capable of simultaneously transmitting and receiving, using buffers for both.
For cases where NewSoftSerial or SoftSerial lose data or interfere with other libraries, AltSoftSerial offers an alternative way to emulate an additional serial port. In some cases, it may perform better, in others is may offer no improvement (while consuming a timer).
No SoftwareSerial approach can rival true HardwareSerial with a real UART, but when no extra serial port is available, hopefully this alternative library can help in cases where the existing libraries have issues.