I've had a couple people in the comments mention more specific and restrictive elements of 40k that I don't generally think mesh well with warscroll design, however, it seems like there is a desire to replicate some of those mechanics, and so I am happy to do so if it makes my work on these warscrolls more enjoyable. Much like my prior 'Age of Warhammer' rules, this is a one page 'Age of 40k' rules set (pdf here) that brings in some of the mechanics that people seem to want without overpowering existing mechanics or forcing them on anybody.
What it basically boils down to is a Vehicle Damage Table, rules for Flyers, and I also threw in Mysterious Objective (since Mysterious Terrain is in Age of Warhammer). Of course the most important of these is the Vehicle Damage Table.
I have frequently been asked by the 40k players who have been helping me play-test these warscrolls what sorts of additional defenses Vehicles have against small arms fire (so they don't just get blown up by crossbows and the like). My answer has consistently been... "none?". This is because I am an AoS player and an awesome dragon can be killed by crossbows and that doesn't bother me one bit. However, it seems like my answer left something to be desired. So this Vehicle Damage Table utilizes the Rend values of weapons and mimics the results of the corresponding 40k table to reduce the impact of small arms fire while also making damage come in fits and starts like it often does. Note that while crossbows can still take out the vehicle, they do less of it and will mostly irritate the driver. To cause any sort of explosion requires at least 1 point of Rend.
Flying Vehicles are the other big thing here, and most of their rules revolve around the ability to Zoom. Zooming makes them count as being in cover, which I like because it's simple and doesn't stack. It requires a little bit of tactical finesse since they have to move straight forward (which I know is kind of subjective, but the vast majority of 40k flyers have a very clearly defined front). Locked Velocity just affects their ability to Zoom (or not Zoom as the case may be) when they would normally become immobilized. And then Strafing Run allows them to go into 'ongoing reserves' as it were.
I hope this hits the highlights that most people were looking for! If anybody tries playing with this set of extra rules, I'd love to hear how it goes (I haven't gotten a chance to do so myself yet). Also, if I've missed any important mechanics from 40k (I thought about including Perils of the Warp, but it would have made it 2 pages, so I'll probably forego that one until I have enough stuff to bother with another page) I'd certainly like to hear what they are. I have a lot of history with 40k, but as I have been sitting out most of 6th and 7th, that increasingly becomes history.