How about "I've been travelling on a weekly basis for the last 3 years, working hours well above what could be considered acceptable, flying halfway across the world at the drop of a hat, and expected to work hours later, through the jetlag (not to mention ending up working on the plane), been forced to endure endless, excruciating business dinners to be patronised by the sales guys, spent time away from loved ones because the boss wants a jolly, flown across the continent because the customer misunderstood a paragraph in a document that could have been corrected with a 5 minute phonecall time and time again. So, if you're not even going to pay me overtime, you can at least ensure I travel in relative comfort, conducive to actually conducting business."

Possibly followed up with "you stingy, beancounting, desk-bound eejits."