Reverse transcription with random hexamers -- full length cDNA possible?

As far as I know there are three common ways for priming when performing reverse transcription on mRNA: 1) polyT-primers, 2) random hexamers and 3) gene-specific primers.

Now, something I am not sure about: Is it possible to generate full length cDNAs using random hexamers? If not, what is the cause? Do you have any literature on this, did not find good information.

I guess with polyT-primers the full length reverse transcription should not be a problem with a polymerase of high processivity and if the transcript is not too long?