Not having acces to all the book, i want to know, is there any Necron ships in rogue trader?

I have read about them in both the 40k lore and in Battlefleet gothic, but do they have any mention in the book?

And if not has anyone made houserules for them?

As far as I know, no Necron ships show up in any of the books.

I am sure that if I'm wrong, someone will mention it, but I wouldn't hold my breath. :|

I know there was a guy around here that made some houserules for Necron ships, though, way back. Search around.

I think this is what Fgdsfg was referring to. THey're not bad, and you can also refer to Battlefleet Gothic resources for inspiration if you want to tweak the rules.

Remember that by the default setting the Imperium has not officially identified the Necrons yet, so if you want to use them as enemies describe the ships, but don't actually say the word "Necron", even as the noiseless robot skeletons have boarded your players' ships and started disintegrating everything in sight.

Certainly there are no rules. One of the silouhettes of the xenos ships in the Purge The Unclean adventure book looks suspiciously familiar too. though, but again that's just a dead part of a space hulk.

Rules would be interesting; they're supposed to be very well armoured but also extremely stealthy. The trick will be picking an armour value which is high enough to be concerning but low enough that it is theoretically possible to punch through.

Broad suggestions:

Necron hulls work like normal armour (albeit with very high armour values). They can reinforce their self-repair capability, at a risk of compromising their flat-out durability. The effect of this is to half the armour value of their hulls, but to allow that armour to count even against lance hits.

Necron ships never take damage from celestial phenomena, and do not count as unshielded where it matters.

Necron ships have no readily discernable components (not that there's a tenebro maze per se but not even a magos really understands how their stuff works).

The inertialess drive means that the number of extra turns/VU movement change for any movement special orders is doubled.

Lightning Arc is a weapons battery - good strength, good damage, possibly an accuracy bonus, reasonably short range.

Particle whip (if you come up against something carrying them) is a Titanforge lance but a critical hit ignores shields as well as armour.

Portals are like a teleportatium but work at a longer range.