Though I haven't done so yet, I'm currently putting together a shoulder bag for duty. I plan to stow it between the two seats up front.
The bag will have the following.
-Spare work-shirt
-Spare work-pants
-Moist towelettes (Yeah, I said it.)
-Fresh & Go Travel Toothbrush/Paste combo. (REALLY NEAT! The toothpaste is IN the toothbrush)
-Spare penlights (Damn Penlight gnome)
-Box o' pens (I only like ONE type of pen.)
-5 sets of gloves.
-$40 Cash
-Turtleneck (Wouldn't want to get a cold
h34r: )
-Personal Meds (Ibuprofen, Benadry, Albuterol, Tylenol)
-Compressible Pillow (I guess relatives sometimes do give something useful!)
This will all most likely fit into a bandolier type bag.
By the way, if any of you need help with gear, whether work related or outdoor related, I have close ties with the gear industry and used to work for it.