These are a very difficult type of funeral to conduct, and the help link below the few examples may be worth a visit.

A Funeral Sermon for a tragic death The Memorial Service of someone who had committed suicide
Funeral For A Suicide Victim - early 20's Let me know what you think of this
Funeral For A Teen Suicide Let me know what you think of this

Funeral Helps Some excellent basic guidelines for planning and conducting funerals, as well as a number of variable quality sermons