Finding one that is built by a builder that has a reputation will be hard. I can build you one, it will be great, but It would cost more than $1K. Getting a used one is probably your best bet given your budget. A new one, built by a person is going to set you back at least $1.5k. I would charge roughly the same as Mesa. The hard part is the cabinet, the speaker, and the remaining parts. Those are fixed costs. A basic cabinet starts at $250 and the speaker is another $150. So just in those two parts, you are $400 deep. The parts to build the chassis are usually around $300-$500 depending on the complexity and quality of parts of the amp. And then tubes, which can cost $100 - $300 for a full set depending on what grade you want to go with. Labor is another big ouch. You are now @ $800 - $1,200 and it hasn't even been built yet. It takes me about one day to build an amp like that from scratch and I value my time @ $500 per day ( call it $50 an hour for 10 hours if you will ). At that, I don't even make any real profit, it would only have me break even on parts and labor. My markup to expense for tools, expendables, utilities, and 30% profit margin will place you right around the $2k mark.
Used for the same grade of an amp is probably around 50% of that. So used may be the better way to go? You can buy kits, and MojoTone is a good source for one at about $850 ( shipping and tax not included ). A person with limited skill should be able to build it in a couple of weekends' worth of time. Troubleshooting is the hard part. Weber also sells a kit that is slightly less expensive, but not overall as good as the MojoTone offering, and even cheaper still is a kit sold by Mable Audio ( an overseas company ) that you may be even able to acquire fully built and shipped for around $700.
I guess my big point is that you probably won't be able to find a new one that is worth a darn for $1k, but a used one should not be as hard a task.