I think if you went to a local cabinet maker in your area you could probably have them make a door that would fit & match the others in your kitchen. You could configure the inside space any way you wanted...shelves or whatever.

I took one out once in a small condo and put in a little rack on wheels (stainless piece) which i had fit with a marble top. on it i kept my bigger baking pieces (mixer etc) and with the wheels it was easy to bring out when in use, then load back up and slide in.

my cABS were impossible to match! but lucky for me, they were painted. i had to extend the flooring under the space (which i did myself...simple tile job) then i sanded the sides of the cabs in the opening and painted them. i have seen spaces like this with a simple cloth cover on them, but mine was nice looking when finished, and since the cart just fit, it looked fine open.

i spent just about ohhh maybe $150 total on that little space, but if you really wanted to make it look great, i've seen a cabinet line that does a roll out tea cart in a cabinet space. i'm sure a cabinet maker could make something similar for your space for a reasonable amount of money.

Thank you both for the tips. I would prefer it to be closed in. Someone told me a cabinet maker would charge an enormous amount of money. Have to find one first.

What about a wine or beverage refrigerator? I've heard that they come in the right size for that space. Good Luck!

Since you only would need a plywood carcass, face frame and a door I cant see it costing over $200. He should be able to make a slide in cabinet. I bet you could also find a knock down that would fit the space. Just get it in the same wood face unstained and find the same door style.
The door can be ordered from about 1000 places and I don't see how you can not match it. Just make sure you match the wood type. Look on the net just to see if you can find one like it. As for the stain any decent woodworker should be able to get pretty close. If you want drawers in the cabinet, then the price goes up, I'm still betting under $300, a knock down should cost about $150 a trash masher is 15". I'm having a cabinet built in an old oven hole about 24"W x 18"H x 24"D with 2 doors and a slide out to match my cabinets for $100.

We have a trash masher and I posted that question to the wife and she said we could always put a trash can in there and cover it with a door. I also like the idea of the wine cooler even if you don't drink wine, put soda in there.

Wine coolers and ice makers are made to fit those spaces, but if you need the storage and can't find a way to match at a reasonable cost (you won't know unless you start looking), just put in a couple of shelves and use baskets to semi close up your things. Make the front of your rol-in cart solid and cover them up. There are lots of ways, but befoer you work on a creative solution, I would look and talk to some folks in your area who could actually do the work or help you find a door to match and see what they tell you.

With 30 year old cabinets, I smell the start of the "as long as we're at its". Bingo. A whole new kitchen! LOL!

Cabinet doors are notoriously hard to match, unless they are very simple. The better option would be as already suggested, to repurpose the space with another appliance or pull out cart. Deliberately mismatching your cabinetry is very popular now, and you could just take off the doors of a couple of adjacent cabinets and have new doors made for the whole section in a different color/style and then add some crown molding in that same color.

Thank you. You are all so helpful. I love the cooler idea. I am going to check out the area first for a new door and if that doesn't work, I really like the appliance idea. I really could use more space for cold drinks. Thank you all so much. I'll let you know how it turns out.

I had that exact issue - an old Kitchenaid 18" compactor next to the sink with older cabinets that I did not want to replace. I decided to go with an 18" Monogram Dishwasher as a second dishwasher. I love it - use it all the time. For me it was much more practical than an icemaker or a beverage/wine refrigerator since I entertain frequently and hate doing dishes by hand!