Ok guys, I will go first. I have had some ideas for a campaign for a long time to do something like Jay N. Keeping with the same solar system idea we did two campaigns ago. The idea being that on each planet that a battle takes place, there would be a third army/race that inhabits that solar system, and when a battle takes place there would be the chance that the infestation race will pop up, and show its ugly face to throw a spin on whatever may be happening in the area. White Dwarf did it a few years back with the tyranid thing, you know, get too close to a bush it sets off a nest. Bam! 20 gaunts come spilling out ready to assault, and devour anyone close enough to be the victim.
It would be a fixed amount of enemy per ambush site, but no limit to how many will keep coming. I thought a d6 roll to determine if they are no longer interested in a fight, and go back to their hole, or the option of destroying the nest with concentrated fire, anyways I digress. The point is we would have markers all over the table, terrain pieces perhaps, and at battle start a d6 is rolled to determine how many, and which terrains are potential nests. The 'nids, when they pop out, would be controlled by the opposing player just to keep it mano e mano you know. I thought that we could even have some bigger nasty 'nids as well, like carnifexs, etc... They would be able to move, and assault as usual, but with no synapse rules, I.E. they are mindless already, and only want one thing from they enemy,FOOD! That way at least the controlling player does not have to worry about synapse, and can just use a set rules list for each type of brood that pops up.
I think it would be fun to have a big, chitin covered monkeywrench tossed into the middle of a battle, just to give both sides something else to worry about besides eachother, the objective, or whatever. I have given this alot of thought, and worked out some of the "bugs"

already on paper, as well as play tested it using some proxied, old, and beat up beastmen as gaunts. I am pretty sure I could get my hands on enough tyranids to make it interesting. A quick painting, some clearcoat, and bam, instant tyranids that everyone in the campaign could use. I have not however gotten over the problems of multiple battles for more than one player in an afternoon that may require more tyranids than I could provide. I mean we could be talking hundreds, who knows.
Anyways, thats a start for my brain things that I have going on in my head, who said that? Oh I did, quiet Maurice, dont be going near the kings feet! With all the great gamer minds in our freakshow, I am sure we could eliminate the bugs, again no pun intended

Thoughts?