I'm a small business owner (I created OpenBeam: http://www.kickstarter.com/projects/ttstam/openbeam-an-open-source-miniature-construction-sys). It is basically a small, nice version of an erector set, that is currently being used for building 3D printers. (See: http://reprap.org/wiki/Kossel).
US manufacturing is *hard*, for sure, for small businesses. In fact, the system is set up so that I'm better off shipping jobs overseas.
We buy our extrusions from a small mill in California, a family owned business. Our first batch was great. We made a small engineering change on the next batch and ordered the extrusions in October of 2012. We received the parts in early December, and the black anodizing was crap - it literally looks like it's been dive bombed by seagulls with diarrhea. We shipped back 700 of 2000 pieces for rework, and we still have not received it back. Meanwhile, I'm out of stock, I have thousands of dollars of backorders that I can't fill, and I still have no idea when I'll get replacement stock back in. And to make things worse, when we complained initially about the quality of the parts, the answer we got was literally "you're small potatoes, we don't have time for you"
Meanwhile half way across the globe, my injection molder (http://blog.openbeamusa.com/2012/05/18/behind-the-scenes-injection-molding/) is churning out parts, 50,000 at a time. He always delivers when he says he'll deliver. With UPS and Expeditors I can get goods landed on my doorstep anywhere from 48 hours to less than 3 weeks for ocean freight shipping. It costed me $1000 to ocean freight half a metric *ton* of parts, and it'll be here in 3 weeks. The reason for going overseas for injection molding is simple: The material we use is a high end glass-reinforced nylon and the only shops the US that can handle it are military and aerospace molders and they demand an incredible premium.
On top of all this, I currently import a bunch of motors, pulleys, bearings for my 3D printer kits, US customs requires that I file an individual HTS classification for each line item, and taxes me individually. I then pay my old coworker's kid $20/hr, which is a princely sum for a 14 year old girl, to do my packaging and kitting. However, If I paid some guys overseas $10.00 a day to do the same job, I can declare my imported goods as "construction toy set" and avoid paying import taxes all-together. Therefore, there are absolutely NO incentives for me to keep the packaging job in the US, except for the short flexibility between an engineering change and getting the change pushed through on the line.
When it comes to export, I'm equally screwed. Until I signed up with Expeditors, there was no easy way for me to export my shipment around the world. So while I have customers in the UK, EU, and NZ/AU areas, for the longest time I had to resort to USPS Priority mail to ship them stuff, and priority mail rates just went up. Surface parcel service was discontinued a few years ago during budget cuts, so unless you are a bonded importer / exporter, you really have no option of doing a low cost export. Meanwhile, I paid US$20.00 for a batch of parts for 2 day shipping for a crate of timing belt pulleys from Shanghai to Hong Kong. There are so many Chinese logistics company these days that shipping is incredibly cheap to move things around in China.
People don't realize that the world is getting a lot smaller these days. The other day a vendor returned an email quotation - 5 weeks after initial RFQ. I had already paid someone else and landed parts in that amount of time. A supply chain is only as strong as its weakest link and it seems like for small businesses there are just no good options for manufacturing.