A Manuscript Witness to a Marcionite edition of Luke?

In a recent article Claire Clivaz has *suggested* that P69 (P. Oxy 2383) should be regarded 'as a witness to a Marcionite edition of Luke's Gospel' (C. Clivaz, 'The Angel and the Sweat Like "Drops of Blood" (Lk 22:43-44): P69 and f13' HTR 98 (2005), 419-440, citation from p. 420).

If this could be substantiated it would be a major discovery, since hitherto we have no actual manuscripts of any of Marcion's works. The contents of Marcion's canon has to be (re-) constructed from the comments of his polemical opponents (esp. Tertullian and Epiphanius, but also others). [For some kind of introduction to Marcion's Gospel see my article on Marcion]

Clivaz makes the following points:

1. P69 lacks Luke 22.42-45a
2. This reflects a 'conscious omission' since 22.42-45a is a logical narrative unit
3. Jesus' request that the cup pass from him (v42) was the most shocking element in the Gethsemane story (for ancient readers, as seen in Celsus; Porphyry, Origen)
4. Celsus argued that some Christians had corrupted the text of the Gospels in order to evade the criticisms of opponents (Contra Celsum II.27 with specific reference to this passage)
5. This could mean that scribes were omitting material from the Gethsemane account.
6. 'This strategy of "negating the objections" by omission would be practical only in a type of Christianity that preserved a single gospel, as did Marcion.' (p. 429).
7. Nothing of Luke 22.42-44 is attested in Marcion's Euaggelion (an argument from the silence of Tertullian and Epiphanius, with the authoritative support of Harnack)
8. The omission of v42 is congruent with Marcionite Christology
9. At Luke 22.61 in P69 Peter (not Jesus) is looking. This avoids any suggestion that Jesus is paying attention to Peter and is coherent with Marcion's avoidance of anything that could magnify Peter's status.

It is an interesting proposal. But can it stand up to critical scrutiny?