Here's the way I look at it. We can only see three demensions. From what I understand scientists are theorizing that there are actually 10 demensions, 7 of which we cannot see.
Yes, you may understand that some physicists are theorizing many dimensions but how about understanding that theory before making speculations. Otherwise it's just going to be an argument from ignorance. In other words: don't be dumb.
Also, try "some physicists" rather than "scientists" as when you just say "scientists" it can lead to the misunderstanding that it is a widely accepted theory across all branches of science. Science has many fields and within those fields there can be many different views on many different things.
Is it not possible that beings are caught in these other demensions and are here with us simutaneously (sp?)?
Go and try and understand the theory and what they mean by a "dimension". Also, try and get decent resources for this rather than other people such as yourself who just hear snippets ("ooh 10 dimensions") and think they understand what that means.
Now with them being in a higher demension I would assume that they could see us. Maybe not, but hey it's an idea.
Underpants Gnomes... it's an idea.
In other words: don't be dumb.
Also, try not to make assumptions and actually try and find out. In other words: don't be dumb.
What if they have the power to show themselves in the demensions we are able to see.
Someone please let me know if this is too far of a stretch.
I really could've just lumped this in together. Go and read the theory: don't be dumb.
I just try to look at everything from all possible angles. 
No, you just make speculations from ignorance and think that just because something can be thought of it makes it worthy of discussion.
I think that humans don't have ghosts but dogs do and I think the ghosts of dogs go and take a shit in some people's minds such as yours which causes stupidity. It's an idea.
I hear that in general relativity time is affected by gravity. I figure as manager it is my job to put the weight of the world on people's shoulders so they end up working less hours in a day and I can pay them less money. It's an idea.
I hear that in quantum theory things can be both alive and dead at the same time, therefore I will be immortal as I will always experience myself as the person that against all odds survived. It's an idea.