Actually, I have used the splitter in question for my 14.5dB directionals.. and the loss isn't that bad.
Another option would be to shoot for the Senao card, which has two external-only connectors ($110-125?)... it is decent, but prism-based, so netstumblers proceed with knowledge..
Your only other option would be running a second Orinoco on the box....
He shall recount his worthies: they shall stumble in their walk; they shall make haste to the wall thereof, and the defence shall be prepared.
-- Nahum 2:5, The Holy Bible, KJV