This may be a somewhat unusual request.
Ideally, I am looking for a bike that has a single chainring upfront, and multiple gears at the rear. The single chainring upfront would be moderatly sized and there would be 5-10 gears at the rear. The rear derailleur would be able to sweep through all the gears relatively smoothly without too much cross-chaining. Are there any bicycles currently on the market with a drive train like this, or would I have to go custom?
I am also willing to buy a bike with multiple chainrings upfront and remove the front derailleaur and shifter, and do the modification to a single speed crank, but I would rather buy the bike as per my specs. I would also be open to a triple chainring bicycle that could hit all the gears in the back relatively smoothly without cross-chaining when the chain is on the middle ring.
The most important feature is that the bicycle can hit all the gears in the rear, smoothly, without adjusting the front.