I think we should focus on companies which already sponsor eSport teams, its way more likely that some of these may sponsor us.
I made some research and came to following list:
HyperX (Kingston)
Thermaltake (They even have a website form for sponsor requests:
http://my.ttesports.com/ctSponsor.aspx )
Verygames (Server)
steelseries
eizo
crucial
benq
razer
msi
alienware
logitech
~Toasty