Odds are, yes. We can design just about anything you can describe to us! Can we produce one of them, next week, to fit your budget? Now that’s the hard part!
New products take time to develop right. A quick description has to be written down or sketched out to give it a solid foundation. Something concrete has to be there, so that all the requirements that can be implicitly hung on an idea can be spelled out. Your requirements will drive every other step in the process, because a design that misses some critical requirement is worse than useless in the end.
 

Requirements will include the dimensions of the design, the minimal function, any bonus functionality, an allowable time line, a typical order quantity and a target price. At a bare minimum! The more details can be provided up front, the faster an idea can be formalized into a design.
Sketches help but they don’t speed up the process. A good machine shop will not accept a quick sketch – this is their contractual document, and they don’t want to misunderstand their instructions! A good drawing will have to take into account the capabilities of the machine shop; some drawings simply cannot be physically recreated without specialized machinery.
The material selection has to be reasonable, balancing cost with availability and machinability. The best material for the job may be absolutely impossible to work with! And, it may not be available without months of lead time.
Finally, the cost will always depend on the number of units. Small batches cost the same to set up as big batches – pretty much – but a big production run can distribute the set-up charges a lot further.
It’s always worth asking. Sometimes the requirements need to change, but usually we can find a way to produce something that works for you.

Build a thousand, it’s mass-produced. Build one, and it’s a work of art. One Mona Lisa; One Spruce Goose; One Golden Gate Bridge.
If you want a work of art, we can produce it. But it will take a little extra.