What size are collectible tv and video release posters?

[holiday]

It's occurred to me that the only tv posters and other ad posters, like HBO, Showtime and video release posters, that I tend to collect are 27 x40 in size.  The assumption that I've made is that anything less than that - typically 24x36, is a commercial release poster.  

Would you generally agree that the collectible versions of other posters like these are limited to 27x40, presuming that they are so sized for use in the movie theater for advertising to fit standard 27x40 displays, as well as in other venues.

[skyjackers]

In my experience of collecting video posters, they come in all shapes and sizes. I think in the US they tend to be 1-sheets but in the UK they tend to vary. I think 27x40 may be the norm now and it does make them more collectable, but I do have some odd shaped US posters too.