D.A. Black (dbo) emailed in to report that his article on conjectures (refered to here in relation to the general discussion here - don't forget to read the comments!) was 'Conjectural Emendations in the Gospel of Matthew' in NovT 31 (1) 1989, pp. 1-15.
It is a useful paper and a good resource for what the title says (no mystery here): it discusses seventeen conjectural emendations to Matthew which have been proposed by a number of different contemporary scholars. He argues that only one is at all plausible and that generally we'd be better off looking more closely at the 'transmitted Greek text'.
Perhaps it is inevitable with conjectures that the one Dave Black regarded as 'viable' but not certain, seems a non-starter to me. For 19.4 Sahlin proposed that Matthew originally wrote ARSEN KAI QHLU EPOIHSEN A. This alpha was meant to represent the numeral 1: HEN; but scribes misunderstood this and harmonised it to the LXX.