Other places to look - maybe for smaller sponsorship needs:
Get to know your local commercial refridgeration guy - in case you hadn't noticed we use a LOT of ice. Might even be able to score a used machine or transport cabinet.
A local or regional fabricator - even if he won't go a rig he might discount modifications or trailer work.
If you have local food locker operations - they might discount or provide your meat.
Need a trailer every so often or a hitch on your truck/car/SUV - talk to your hitch or trailer rental guy or a local fabricator - you might be surprised that they'll let you use the stuff for some advertising.
This is the kind of "figuring" I do every evening and while I'm driving around between my offices.
Southern Brethren BBQ Competition Team
"It's all about getting paid!" - Myron Mixon
"I love being hated in my hometown!" - David Hair
KingFisher Gator Rotisserie cooker, WSM, Stainless 5 burner with IR gas grill, Turkey Fryer, Weber JD Commemorative grill, slightly used Bandera chamber for future use as a cold smoker, Masterbuilt 40" insulated ELECTRIC smoker