Just to add to the discussion here is what I found regarding "Trailers" on the txdmv.gov website. There is a separate listing for trailers with different requirements for getting it titled and registered in Texas. Here is the link.
TXDMV.GOV - Trailers
Below are excepts from the site in
italics
Determine the type of trailer you have
Start by looking on the trailer tongue. This is where you are most likely to find the manufacturer’s name, which confirms you have a manufactured trailer. If you do not know whether the trailer is manufactured or homemade, it must be inspected by an auto theft law enforcement officer.
If your manufactured trailer's gross weight exceeds 4,000 lbs., it must be titled. Submit the following documents to your county tax assessor-collector office:
Evidence of ownership:
New trailer: Manufacturer Certificate of Origin*
A completed Form 130-U,
Applicable fees
* The Manufacturer's Certificate of Origin (MCO) is the document that allows you to register and/or title a new trailer. This is your trailer's "birth certificate," showing its unique identification information. A trailer manufacturer is required to provide a MCO to dealers or purchasers for every vehicle it manufactures.
Trailers with a gross weight exceeding 4,500 lbs. must pass an annual safety inspection.
In some cases, you may be asked to provide additional information such as:
Weight Certificate, and/or
Photograph of trailer.
For information about all required documentation and fees, contact your county tax assessor-collector office.
From reading this is seems all you should need is
1) Evidence of ownership (Bill of Sale)
2) MCO from ETI
3) Completed Form 130-U
4) Pay fees
5) Safety Inspection required if actual trailer gross weight exceeds 4500 lbs.
I have not contacted the County Tax Office or had personal experience with the process or what is required by the local county tax collector as some of you have, just throwing this out there for discussion so we all may learn something from it.