Welcome to the forum. and congrats to you and your bride
Judging by your description of yourself, I'd say to build one yourself. If you have the skills, the space and the time (or have access to someone withe skills space and time), you can do it over the Winter and be finished in time for Spring.
This is why you should build it yourself.
1) You can control costs by installing exactly what you want/need and building it exactly the way you want.
2) You can control how much it will weigh
3) You can make it look how you want
4) You can buy things along the way, you don't need to drop a big chunk of change down at once.
5) When you are finished, it's paid for, no payments.
6) When people ask you for a tour of the trailer, you can say, "Yes, I did build it myself."