Thabet points to a site called Ihsanic Intelligence, which has published a document called The Hijacked Caravan: Refuting Suicide Bombings as Martyrdom Operations in Contemporary Jihad Strategy (PDF).
The document examines and refutes the specific claims made by those who say that suicide bombings are Islamically legitimate, and presents clear evidence that both suicide and murder (much less the two combined together) are forbidden in Islam. Their conclusion:
The technique of suicide bombing is anathema, antithetical and abhorrent to Sunni Islam. It is considered legally forbidden, constituting a reprehensible innovation in the Islamic tradition, morally an enormity of sin combining suicide and murder and theologically an act which has consequences of eternal damnation.They plan to present this document to the United Nations Social and Economic Council and to ask Muslim scholars worldwide to sign it.