Are the SG melody makers about the same size as the regular SGs are? As in, neck size, nut width, body size? I'm wondering if I could shove a trapezoid tailpiece on one. Thanks.
It depends on the year and model.
For example,a '61 reissue has slightly different spec. list to a standard made in 2008,though you should be able to put a trap. tailpiece on(assuming it's also from an SG) s they don't tend to vary by a great deal.
It's a '68 trap tailpiece from an SG Custom. I just like the melody maker SG a lot and would think it would work granted the body and stuff is all the same size. Most of these I've seen have already been reamed and stuff. Man I wish Gibson made a reissue of this.
Well as far as I can remember the SG melody maker has a wraparound tailpiece and the '68s had tune-o-matics?

Other than I can't see any problems,I spent some time shopping around for an SG (most were originals from the 60s and 70s) and there were different neck profiles etc,but the body sizes all seemed to be about the same.