When I looked at the design of my Coleman Coastline, I did notice that venting had been thought of quite well in that the tent is covered in them
On the outside, the obvious ones are at each upper corner front and back, where the vents have a very clever strap that is velcro attached to hold them open when windy etc. These are all meshed inside to stop bugs:

Outer Vents Shown
On the inside, the attachable sleeping pods have matching mesh panels at the top, and they do indeed keep the air flowing nicely, giving a lovely fresh feel when waking up in the morning

Inside View of Outer Vents

Example of Inner Pod Matching Mesh Panel
Finally, Coleman have their own Cool Air Port which features on their latest models, designed like a cat-flap with zip closed inner screen and zip closed mesh panel too. Can be used on it's own, or with their own design battery powered Cool Vent Fan:

Cool Air Port viewed from inside
I have to say that I've noticed how well all the venting systems work in this tent. My previous smaller Vango Tunnel Tent did have small vents but never felt quite as fresh and clean aired as this one does....
As you probably already know, I cook inside (not wanting to start on why I choose to do all over again), and even cooking smells still disperse quickly - but I do have the door open anyway which obviously helps a lot....
Oh and one more thing.... Coleman have a nice obvious warning label sewn into the inside of the tent...... it's sewn onto the outside of the sleeping pods, and warns not to cook inside that pod

Warning Label Arrowed
I just had to leap to the defence of Tunnel Tents - not all of them have poor venting













