Well using your information, if they were roughly at 7000' as you say and 2 miles from a VOR, my guess tells me that they were probably established on a hold over said LAS
VOR. Due to where you were standing looking up, it would appear that they are in close formation, but infact, one could be at 7000' and the other at 8000', for example, giving the false impression. That is a common occourance at busy airports/airspaces where traffic is very high.
I remember seeing photos on here recently about 3 SAA aircraft doing a close formation for an audience. One was an A346, the other a 744 and 747SP.
Hope that helps!
You are said to be a good pilot when your take-off's equal your landings.