When I stayed at Skylofts, I was a bit confused about tipping (although I had sent bltserve some questions in advance and he provided good advice).
I tipped the Maybach driver $40 for the trip from the airport to MGM Grand. The Maybach wasn't available on the way back, so the trip back to the airport was in a limo, and I think I tipped the limo driver $30. (It did occur to me that the tips were more than a cab ride would have been, but hey.)
Once arriving at MGM Grand, a concierge meets you and takes you up to your loft for check-in. After check-in, I didn't tip the concierge (I didn't really think about it, as I was excited about arriving at the room and tired after a long flight), but later I wondered if the concierge was expecting a tip. bltserve: what do you do?
Immediately after the concierge checks you in, the butler provides a tour of the loft. This was the only time I saw the butler, as I never used butler service for the remainder of the week. I was a little confused about tipping etiquette here, too. I wasn't sure if I should tip the butler right after the tour, or later in the week, and I wasn't sure where to leave the tip. I must admit tipping kind of confuses me, especially in a Skylofts kind of scenario.
I did leave money each morning for housekeeping and most evenings for turndown service, and tipped the bellman $10 when he delivered my single bag.
I'll be returning to Skylofts in December, so I'll have an opportunity to be confused about tipping once again.