Keep video screens level to the audience's viewing perspective. But other than that, let the trusses go wild - have vertical trusses sitting on the floor, have some trusses at angles, etc...if you get the magazine lighting and sound america, look at the elation ad on the back - top left corner - cool angular truss idea. Have ground based fixtures (ellipsoidals) shooting out from behind the crates and such up in to the air, maybe through the truss. Light the truss - use truss warmers (maybe led pars?). If you've got the budget to add a few fixtures, get 4 or 8 Wiedamark LED pars. You'll thanks yourself. If any of that doesn't make sense or seems vague or hurried, sorry, I just finished a strike and I'm about to go to bed.
If you want to have skewed projection, maybe get the video designer to record the promos and things at an angle for playback - but you'd want the main videos that are being featured to be played back at a normal viewing angle for the audience. I'd yell and scream if I had to tilt my head to watch a video; however cool the setup looked.
Saying yellow police beacons prompted caution tape, or police tape - for scenery type things. But you're fairly limited with the height of the ceiling. Having a mover sitting on a wooden crate would look pretty 'Half Life'ish, pretty awesome.
Having done too much work in a room with a 12 foot ceiling, I suggest you do some good scale drawings and pay attention to photometrics. If you've got a 12' ceiling and say a 2' platform. You only have 10 feet of vertical space. You jack the truss up to the ceiling and then you have instruments hanging down from that, cutting the relative height of the instruments to the stage down to around 8'-9'. That's not a lot of fun. Musicians tend to not like lighting instruments hanging 2' from their heads. You need REALLY wide angle instruments. I'm assuming you have some sort of front light truss as well... these will be right at eye level with your musicians so they are going to complain about not being able to see the audience. Try to do truss off to the sides so that you can get some interesting cross lighting angles. Light from the truss in the back pointing forward is going to be either straight in the face of the audience or at too steep of an angle to be useful in lighting the band.
Not to be a downer... there is still a lot of fun to be had. Just do your design homework or you may find it's much harder to light the stage than you expected.
Though overdone....A a relatively cheap suggestion for the set is Spandex Panels. You can twist them, tie them off at odd angles, and create some very nice transitional color effects on them fairly easily. If you're careful about the angles, you can even use them to project onto. Most commercial LCD Projectors are bright enough now to work on a...slightly less than optimal surface. Plus you don't have to worry about them fitting exactly into a given space, as you can just tie them off, and stretch the excess out further in another direction.
Just make sure that they've been sprayed down with a fire retardent, and that you have the certificate onhand.