I am completely partial to Commercial Lever Espresso machines for several reasons. So, I would encourage you to look into going the way of Blue Bottle of San Francisco (and soon to be New York), the Lux of Phoenix, and Cafe Vita of Seattle. After proper training on a lever, you can pull shots that are superior to any machine on the market. They really help bring out different levels of flavor from your coffees. The pressurized paddle semi-auto machines, Synesso, Slayer, etc. are simply trying to electronically mimic the lever's pressure profile, as that is the only pressure profile proven to bring out better flavors from the coffee compared to the standard constant pressure of a normal semi-auto commercial machine.
The overall build of a lever is very simple and easy to understand. If you look 'under the hood' of one you will notice that the only electronic parts are the pressure stat and the heating element. Compared to the massive amount of engineering and parts that go into the modern pressurized paddle machines, fixing a lever is a snap. You would be more than capable of diagnosing and fixing the small number of things that can go wrong with one. This way you do not have to depend on a repair person, and can keep the shop up and running.
You can install a PID to regulate water temperatures pretty easily. This would really make a machine that is the best of both worlds. It would have the look of an early classic espresso machine, but the PID'd temperature control of the modern monsters.
They are quite eye catching as well, as most people have never seen one. The movement of multiple levers at one time is quite mesmerizing.
La San Marco currently makes a great commercial lever machines that is not outrageously expensive like a Kees Van Der Weston Idocompresso or a Bosco. San Marco is actually the oldest espresso machine manufacturer that is still in business today. Rancilio has a very strong lever named the Classe 6 LE. Conti has a great one called the Classica PM. Astoria also makes a very visually appealing lever the Rapallo, which is more expensive than the others. The San Marco's sport a 55mm portafilter basket. In the lever world the more narrow the basket the more 'layered' the flavors. This quality is pretty unique to narrow basket lever machines.
There is actually a 2 group Rapallo on craigslist New Mexico and they are asking $3,000. They repost it every few weeks, and is has been on there for about 2 months now, so I am sure you could negotiate a better price. Those retail for about $7,000.
I know they are not for everyone, but in the hands of the right person you really can not beat them. It would definitely set you apart from the other shops in the area. Just my 2 cents.