These devices are essentials in building healthcare applications. I'm trying to build an end to end wireless network from BSN via WiFi to the central server.
I did a review about the commercialized BSN available in the market, and I found that few of them are commercialized but many research platforms were developed and not commercialized yet.
An option is to use the Arduino - Lilipad platform and the available sensor and actuator nodes. The Lilipad has a circular form pattern with large I/O holes around it that allow integration to clothing. You can either solder the connections, or use special conductive threads to make wired interconnect through the clothing. However, I'd say this is more of a prototyping platform than a commercially available BSN.