Personally, I disagree.
I personally think you should offer it. You say you are a quality-driven shop, and when people expect quality they also expect to be able to customize their experience. Your idealism is admirable but honestly, I don't know if it can cut it commercially, and as a customer I would be deeply disappointed if my request for something easy was rejected just because the barista or shop didn't want to do it.
PS: I wish you all the best but I don't know if there's really a market for a real coffeeshop in Peoria.
I'm with Benza on this one.
It's generally the chain restaurants and not the quality driven places that let or even encourage the customer to have it their way. You have probably heard people say about a great restaurant in your town 'Damn that place is great, they have the absolute best (insert dish here).' You will not hear people say 'That place is my favorite because I can get extra pickles.' Pickles are great but no one will ever consider a restaurant great because they can get more of them. Go the the best restaurant in any city in the world and you will eat what the chef has determined is the best preparation of his chosen ingredients. Do some think this is snobby? Sure. But that's unfair. Anyone who appreciates quality and a unique experience should understand the chef's motives.
The chef is not a snob because he wants people to enjoy his creations as intended. The chef has spent countless hours and sleepless nights perfecting the dish. Has the average customer done this? No, and they shouldn't. It's the chef's job to create interesting and delicious meals and if the customer enjoys the restaurant they should trust that the chef will use his ingredients in a way they will enjoy.
This same approach applies to coffee. We generally use 2 and no more than, I'd say, four ingredients in a drink. If you are anything like me I'm sure you've spent tons of time and some sleepless nights trying to figure out the very best way to roast or prepare coffee. Therefore the way the barista chooses to prepare the drink is better than the way the average customer would. This is not snobby it's just that if you dedicate a good portion of your life to making the best coffee then as long as you use good ingredients you will make coffee better than most.
If the customer is a car salesman I'd expect them to be able to sell a car better than I could and probably wouldn't give them any tips on how to move a car off a lot. Why should a customer think they are better at the craft of properly preparing coffee than a great barista? It's nothing but rational to think that someone who practices a skill or craft daily, be it making coffee, selling a car or performing surgery, will be more skilled at that craft than someone who does not.
I say all of this knowing that this is a peer group and would never have this conversation with a customer. I think that is the key to the whole snob debate. Just do what you do to the best of your ability and don't give off the vibe that you are better at anything than your customers. Making awesome coffee is pretty cool but don't let that go to your head. After all to most people, even those who really enjoy it, it's just coffee. Really in the grand scheme of things it really is just a brown liquid that tastes good so who really gives a shit. :-)
By the way, I wouldn't advertise this to my customers, but I'd make anyone anything they want as long as I have the ingredients on hand. I'd somehow let them know that if they enjoy the drink that next time they should try it my way and they will really like it. Or you could always offer to make them the drink your way and if they don't like it replace it with their 'customized' drink free of charge. Good luck!