I had the tongue on my trailer fail at the front crossmember last summer at the most inopportune time; a week before one of our annual family camp outs. Most places, including the dealer, didn't want to touch it.
I found an RV collision shop willing to take on the work. They successfully replaced the entire tongue with thicker-walled tubing and additional reinforcements, and even had it finished for my trip the following weekend. It wasn't cheap though, and they said they had one of their guys on it for over 40 hours. Although it seems like a simple repair, the box of the trailer had to be separated from the frame so they could make the necessary welds. The shop said this was the first time they repaired something like this, and next time around, they would quote it for at least another $500 over the $1,800 I paid.
I think part of the reason shops are hesitant to tackle a project like this is due to the potential liability if they are the last ones to touch it and the repair fails while driving 65+ mph down the freeway.
Hopefully you're able to find someone to help you, because it seems like such a waste to scrap a perfectly good trailer due to a repairable frame issue. I tried claiming the repair on my insurance, but they wouldn't cover it, as it was deemed a mechanical repair/maintenance issue and not a total loss. If I would have had the tongue completely snap off the trailer while in tow, they would have paid the claim, and it would have been substantially more!