Research that and look around at other book stores. You'll find the one doing it.
http://www.forbes.com/sites/philjohnson/2012/05/10/the-man-w...
Is it so expensive that you could burn out three cheap laser printers a month for a fraction of the cost? What if it was one moderately expensive printer every two months?
What if you had a Raspberry Pi managing your print queue across multiple networked printers and you bind them with a surplus GBC machine? You could keep a supply of "nice" pre-printed covers available to wrap around books when they're ready.
One nice thing about this is that you could start small, and scale fairly easily. Use human labour (that's already running the shop) to fill in the gaps in automation.
It might be worth looking at Don Lancaster's web site (tinaja.com) for some thoughts on how to do this stuff before any pre-packaged solutions existed (look for "print-on-demand" resources).
I like bookstores a lot. I hope you'll be able to find a way to make it work for you!
I'd love to find someone who wants to get involved and do just what you describe.
This is a solution for a low print run rather one-of-kind printing but it works for him.
If you can get your prices competitive, there might be an opportunity for you in thesis printing.
If you could get your prices so low that a professor with a ready-to-go textbook in PDF form could get it printed on demand cheaper than going through regular publishers and college bookstores, that would be a big opportunity right there. By all accounts college textbooks in America are very expensive, but neither authors nor publishers admit to making much profit, so presumably there's a lot of inefficiency there. Could be ripe for disruption.