FYI, for US readers, Sunon makes an equivalent fan, the KD1204PFB1. It's even 2mm thinner than the ELINA fan, which might help it fit better, or leave room for rubber washers for mechanical isolation. It's about $9. You can buy them online from Plycon at http://www.plycon.com/sunon40.htm

You can just whack off the RPM lead and 3-pin connector and wire it how you like.

If you're a madman about the noise, you could use a dremel or milling machine to cut the fan holes out (make one BIG hole instead of all the little ones). This would help to greatly reduce wind-turbulence related noise - air is going to get very turbulent through those sharp metal holes. Be careful, of course, but a 40mm fan probably won't take off your fingers even if you accidentally stick 'em in there.