4 times as large in each dimension would give you 4^3, or 64 times as much volume (and presumably crew).  You only need about 2.5 times in each dimension.

Mike

Hum.  I wonder what the tonnage of those Battlefleet Gothic ships was. Probably something ridiculous.

*edit* Some browsing of the WH40k Lexicanum puts the Lunar class at 28 Megatonnes with a crew of 95,000. Heh.  I think the official stats somewhat overball it, given how ships are portrayed in the rest of the fiction. I mean, they're supposed to be huge, and carry whole divisions of troops, and so on. But you'd need an entire chapter of space marines, minimum, to conduct a boarding action on a ship that size.    A Strike Cruiser is only supposed to base about a company (?) of space marines. et. al.

That actually doesn't sound that far off given that ships in 40k are all supposed to be several km long and are fairly packed with crew. The Enterprise (US CVN, not Star Trek) is about 95k tons, 350 meters long by 80 wide at its max, and carries 6000 people on board. Scale that up to being 10 times as wide, long, and deep, and it becomes roughly the size of WH40k cruiser but with an expected capacity of 6 million crew and a weight of 95 million tons. Presumably in the far future there is only war and lighter building materials.

I too have a WH40K flavouring although the full imperium list I use is filled out with Manticore, Nelsons navy and so on, its been in use for every 4x I've played over the years.

If your adding a 40k flavour I will attach an an excel sheet (saved as csv so you'll need to adjust the columns) with the design names I import every iteration, which aren't all canon, but do have the flavour (has Imperium, Traitor, Eldar, Dark Eldar, Necron, Tyranid, Tau and Ork). I say "design names" as I make a design and call the first ship of that class to be built that name. Maybe you can glean some stuff from it to flesh out the theme.

The ranks are taken from the Lexicanum so are pretty acurate.

Ground troops get named depending on type as well, Marines become Legion I, Legion II etc and are generally three Battalions consisting three Marine units (1st Company, 2nd Company etc) and an assault unit named a "Tactical Dreadnaught Support", the fourth battalion are heavy Heavy Assault Battalions named Heavy Support Squadrons, Ive included that on the csv too. I did go through a phase of naming the Heavy Assault Battalions as Titans, and assault Battalions as Scout Titans but that can turn out to be a lot of Titans in a long game. Garrison troops become Arbitrators under a Brigade Headquarters renamed Adeptus Arbites Provost. Imperial guard are left as is, usually just prefixing their name with the Division (Like 1st Terran, 7th Armd etc).

EDIT: Updated the Imperium.csv as I'd copied over the design/shipnames from the wrong place

When I finally get around for my test campaign for v5.70, I suspect there may be a flavour of 40k involved . I forgot to mention it but v5.70 includes a new Warhammer 40k commander name theme. Below is a quick example of some names it generated. I've also added two new ship naming themes, one for WH40K Empire and one for WH40K Chaos, with over a hundred names in each one.

Steve

That's great Steve, but I may get a bit concerned if any of my commanders are named Horus Lupercal

Well, bloody hell stevey-o...thats just plain out awesome. Though it does make me feel kind of old to remember the days when nobody other then some serious tabletop gaming nerds had any idea what warhammer was, let alone 40k...And I agree, 5.7 will be nice

Ah yes the good old days of desperately trying to butter up the one guy in school who was a) Actually any good with a paintbrush and b) had a real interest in 40k to paint up my own sad little collection.

Can't wait for 5.7 either! Will be very interesting to see what comes out of the bureau of ship design and AARs.

5.7 can't come soon enough.

@Xeryon - You can manipulate that with the 'galaxy size' setting.  Also, if you want a 'gateway' system, you can go into SM mode and manipulate the jump points (or delete systems entirely) until you get a result you desire.   Be wary, as always, of NPRs discovering JPs into your existing systems.

I know I can adjust the settings for this.  My comment was in reference to my amusement at the variety that was randomly generated initially.