Technically it works, but if the AHJ asks if the 2-pole breaker is intended, and UL Listed, to protect a line-to-neutral load you may have a tough time answering.
About half of the time that I have seen this type of installation it has been passed, and gigged the other half.
Also 210.23(A)(2) prohibiting receptacles on a circuit feeding 'fixed in place' equipment would come into play.
Besides...if it were that easy why would they sell disconnect switches that have a GFCI already installed in them?
Go to www.geindustrial.com
and search for DET-382 to see the GE product; several other manufacturers have the same thing.
IMHO I would suggest that you run this question by the AHJ to make sure that you won't have to tear anything out and do it over.