You can check with different brokers, for a rate to move your box. Landstar and Mercer Transportation have their Texas and CA broker/agents listed on their website. DallasMavis does as well. Thing to remember about brokers..they are gonna make their $$$ off the movement.
You can post your "box" at both InternetTruckstop;
http://www.truckstop.com/
and Getloaded;
http://www.getloaded.com/.
Post it as flatbed LTL (less than truckload) and post the estimated weight as well as the dimensions, the city where the "box" will be loaded, the city where you will take delivery, the miles bewtween the 2 points, and the rate YOU are wanting to pay.
There are many flatbed's and stepdecks out there, as well as a few RGN's, that will throw your box on for the extra revenue, if they have the space and the weight available. Many flatbed and stepdeck operators are out there, hauling only LTL shipments and making good money doing it.
If you want that box in a hurry, expect to pay Truckload rate ($1.80 per mile or more + fsc of 25-26%). If you are willing to let the truck make it's money hauling ltl, you should be able to receive it within 2 weeks of shipment, and pay a rate in the area of $1300, with fsc included.
It's entirely possible you can find someone with a load of pipe, that weighs less than 43,000 pounds, who will through the item on top, if it isn't going to put the load over 14 foot in height. Lot's of operator's look for some gravy to put on their meat & potatoes.