It is possible if you have some extra hardware. It has the software for wifi already and just needs one of the below to work. I was getting a wireless connection during testing without a pigtail. Signal strength was ~50% with the case on and right beside my WAP.
http://img.dxcdn.com/productimages/sku_149922_1.jpgYou can also do what laptops and other devices do and use an INTERNAL antenna, too. Like this one:
https://cdn.techship.se/uploads/images/193/10101_internal_antenna_2j.1359464154.pngThere are many different kinds, just do a search for internal antenna. Does anyone know what the enclosure is made of? It looks like steel, so that could be a problem. If you have a strong signal, it might just be enough to use for mining though. Having the antenna glued/taped to the enclosure will probably help a lot (partially use the enclosure as an antenna?). Otherwise you could always route that cable to the outside and tape the antenna to the side or something. Someone has to try and let us know if that's even necessary.
I think an internal antenna would be easier than drilling holes, installing the connector and then a protruding antenna. Btw, I use WiFi on all my S1's just to save on cables and switches/access points, and never had an issue with network connectivity.
