I guess there are only 3 OEMs of these pen devices? this should be N-trig (MS Surface, Sony), Wacom (Galaxy Notes?) and Synaptics (Acer, Dell etc.).
I just tested a new (noname) Windows Tablet with digitizer coming to the stores in these days, but the optional advertised stylus seems far from being delivered to the stores.
I would like to test some of existing pens in the mean time.
Which are most likely working? Can I check some system driver of the tablet to see the technology it supports? Any further ideas?