i personally use a hugo army duffel bag. its too big actaully, i use it more for camping, but it can carry my emaxx, and 3 more 1/10 cars or trucks hahah and some tools. just type in army bag or army tote military etc.. but heres a few others:
http://www.wing-tote.com/
http://www.wing-tote.com/deluxTruck.php
http://cgi.ebay.com/ws/eBayISAPI.dll...link:middle:us
http://www.sears.com/shc/s/p_10153_12605_01455040000P
just be sure you check the width of bag and your truck...alot of bags arent that wide