A quick search on-line turns up the following, 1/72 scale Hudson kits, suitable for this build:
Click on Image to EnlargeFirst of course there is the ubiquitous Airfix kit - this box art depicting an attack on a U-boat (very good!

). However, note it is a MkI; still requiring some engine cowling/nacelle modifications to convert to a MkV. Plus, exactly as feared, I have already seen indications this kit is indeed rather crude; it would be hard to swap my conversion idea using the better Academy Ventura kit in favor of building one of these.
Fortunately, there is a better kit - better in all respects - to be had:
Click on Image to EnlargeA ready-made MkV, from Italeri! And the camo depicted here really grabs me a lot better than the other, "brown boxcar" schemes (though we'll see what's accurate for the Hudson #V9253 in question.) On eBay, this kit is going for a price comparable to my Academy Ventura II; this is the swap that would most interest me, by far. (So, if anyone has one,
eMail me!)
A kit which is a bit much for me, both in terms of cost and of detail that I really don't plan to exploit - is the Classic Airframes 1/72 kit:
Click on Image to EnlargeThey have released (at least) two such Hudson molds - either that, or the one kit contains conversion parts for anything back to the Hudson I and the commercial airliner - because I saw even more boxings of those. However
this box art - which I am sure accurately reflects the contents - depicts engines looking identical to those on the MkIV/V. Meantime, I
seriously love this
artwork - not for the aircraft, which frankly is in the way of the
spectacular seascape, and ship under attack, in the background! Of course, if anyone wants to swap this boxing of
this kit for my Academy Ventura, I won't turn you down.
So, that's a pretty darn good selection, above; a Hudson for virtually every price/quality range. If anyone(s) has any more to suggest, in 1/72 scale (I don't have room for anything larger that that), definitely sing out!
Cheers,
-Matty