I think what I said on sectorgame about your previous model even moreso applies to this one - there's just not enough shape for it to be a ship in my mind. Sure it can be nicely greebled, but if it has no shape it's not going to do a lot of good. In fact to be totally honest it far more reminds me of the sort of greeble you might find attached to a bigger ship than a ship in its own right - as Wanderer has said, a piece of tubing or somesuch.
If you look at the FS ships, none of them with the exception of the terran cargo crates is as simple in shape as the ship you have here. They have extrusions, indents, curves, angles, fins, engine pods, rotating bits, docking ports, arms, holes, spindly bits, bridges, superstructures, fighterbays, landing strips, towers and just generally....stuff.
You seem pretty competant with greeble making already, so I'd definitely suggest you try focussing more on design features now.
If you find it difficult to come up with designs in the modelling program, come up with them on paper - just doodle with angles and shapes until you end up with something that looks like a ship. That way you'll find it far easier to actually model it.
