The difficulty is this. Tabor and Jacobovici appeal to the presence of resurrection imagery in Jesus' teaching on the "Sign of Jonah" (Matt. 12.38-42 // Luke 11.16, 29-32) as being present in Q and so linked to the pre-70 period. Indeed, it is key to their case that the earliest Christians used Jonah and the fish imagery as a means of pointing to their belief in the resurrection:
Our discovery in the Patio tomb is unprecedented in that it reflects one of the earliest sayings of Jesus, preserved in Q, contemporary to the generation that saw him and heard him teach.*However, and this is the important point, the use of resurrection imagery in connection with Jonah does not appear in Q.
The Sign of Jonah appears in Q 11.16, 29-32. Jacobovici and Tabor rightly refer to the IQP's reconstruction of the text of Q** though they do not quote it. It reads:
Q 11.16 But‚ some .. were demanding from him a sign. 29 But .. he said‚ ..: This generation is an evil .. generation; it demands a sign, and a sign will not be given to it — except the sign of Jonah! 30 For as Jonah became to the Ninevites a sign, so also‚ will the son of humanity be to this generation.The material about Jesus being in the belly of the fish for three days and three nights is universally regarded by Q scholars as Matthew's redactional addition:
Matt. 12.40: For as Jonah was three days and three nights in the belly of a huge fish, so the Son of Man will be three days and three nights in the heart of the earth.In other words, it is Matthew's gloss written in the post-70 period and it is not evidence for what Christians in the earliest period thought. To put it another way, there is no evidence from the earliest period that imagery from Jonah was used in connection with Jesus' resurrection.
I understand why Jacobovici and Tabor wish to stress that Jonah is mentioned in connection with the resurrection in the pre-70 period. They are right to note that Q, if one accepts the hypothesis, does indeed mention Jonah. However, the mention of the sign of Jonah in Q is connected specifically with the preaching to the Ninevites. Q experts like Kloppenborg link it with Q's deuteronomistic theology and with preaching of repentance and the rejection of God's prophets.
Scholars often tire of studying the Synoptic Problem, but it does repay careful attention, especially in cases like this, where the devil is in the detail, and the evidence for pre-70 resurrection imagery evaporates.
* Tabor, James D.; Jacobovici, Simcha (2012-02-28). The Jesus Discovery (Kindle Locations 1115-1117). Simon & Schuster, Inc.. Kindle Edition.
** Chapter 3, footnote 5.