Compactness is supposed to be a DX draw, but where is it?

I don't think you are correct on this one Craig. If you take two DX and FX equivalent zooms like the 18-200 (DX) and 28-300 (FX) which have pretty much the same field of view and relative apertures, the weight and size go down significantly. For example ...

18-200/3.5-5.6   weight: 565gm   filter size: 72mm    length: 96.5mm

28-300/3.5-5.6   weight: 800gm   filter size: 77mm    length: 114.5mm

I think the proposition put by the OP is valid in that there's not a similar selection of fast, good quality zooms for DX as there is in the FX range

Thomo