If your radio does not support the mixing to use two channels for the elevator, you can get a reversed servo and use a regular Y.
Standard JR 537
http://www.horizonhobby.com/Products...ProdID=JRPS537
Reversed JR 537
http://www.horizonhobby.com/Products...rodID=JRPS537R
Less expensive is the Hitec 425
http://www.servocity.com/html/hs-425..._sport_bb.html $15 standard and $25 reversed
If you want more powerful, or faster, servos you can get several different reversed versions form JR; and Servo City offers reversed versions of many Hitec servos.