Used to, on a limited basis. Stopped it in favor of higher profit business. Glad I did. Now I have less revenue, but also less labor, less COGS, more $/frame, more profit $ and way more profit %.
That business is easy to buy -- just get on the bid lists and bid the lowest prices. The customers are generally the most demanding, but the least loyal and most unscrupulous. If they can string you out for 6 months before paying, they will do it.
I believe it's the riskiest segment of our industry. Big dollars & working capital requirements, but lowest profit. One mistake, and you lose.
However, one of the fastest-growing segments of our industry is "factory framing", aka "OEM" (which means Original Equipment Manufacturer. Don;'t ask me how that term applies.) These companies are well-financed and start with 10,000 to 100,000 square foot production shops, high-production equipment and task-specific workers. Most of them are internet-active, too.
Those guys are set up for high volumes. We're not. If you choose to swim with those sharks, be careful. That's how I see it, as a small shop independent.