So recently I've been throwing around the idea of getting rid of my tailgate nd fabbing essentialy a swinging tire carrier in place of the tailgate, has any one done it?
Some soft tops snap, others have a track that you tuck the seam into. seems like you could do it either way though. I'd be interested to see what you come up with. For what it's worth, I found it really challenging to work with my soft top in temps below about 50* or so, which may not be much of an issue for you on the coast.A soft top rear window snaps onto the tailgate right? So if it was the same hight a softtop might seal

i wonder how this guy handles the dust and fumesHere is one I.saw that's cool. I like the idea if your in a warm state

You could ditch the tailgate, and use one of these off the hitch... http://www.tiregate.com/hg_series_0.shtml
I seriously doubt it could take the stress of any heavy wheeling, but it does claim to have the ability to hold up to a 40" tire.