When ever we go to Madison or Milwaukee on I90/94 I always see atleast 5-6 transports. A couple of times I have seen F550, C5500 and other medium duty low-pro trucks with good size flat beds hauling 2-3 pop-ups and towing a TT, once I saw one of the trucks with a TT on the flat bed towing another TT. It just makes since, haul multiple units make more money.
TT-2013 Passport 3220BH
TV-2004 F150 FX4, not exactly stock...
with 2001 Kodiak K215: 2010-10, 2011-12
with 2012 Grey Wolf 26BH: 2012-19, 2013-24, 2014-11, 2015-6
with 2013 Passport: 2015-13, 2016-15 booked