The question was pretty much answered, but I'll pitch in as well.
At LAS, there are two different ramp towers; one on 129.17 (previously 124.4) that covers the A, B, and C gates, as well as the International terminal. Their tower is located above the main terminal, but is separate from the actual Tower. The other ramp tower (127.9) is above the D gates. The actual FAA ATCT is in between them (you pass it on the train to the C gates), so you can definitely see the separation there.
What is interesting is that sometimes when an arrival gets in, Tower will give them the taxi instructions, and have them contact Ramp directly. You'll hear that quite often on the LAS Tower feed.