Over the Range Microwave
You probably mean 36" width x 12.5" depth x 12" height"?
There are a number of 36" wide OTR microwave oven/hood combinations available (see the following link) as well as a mounting kit to install a smaller 30" model in a 36" space.
LINK > 36" OTR Microwaves & Accessories
Unfortunately, most microwaves of that type are in the area of 16-17" height and 14-15" deep. Since there are only 3-4 actual manufacturers of that type of microwave in the whole world which are just rebranded with different brand names, I doubt you'll find much difference in those specifications.
The Appliance Information Site
- 15 Old House Features We Shouldn't Abandon
- 17 Tiny Bathrooms We Love
- 16 Designs for a Low-Cost DIY Coffee Table
- Insanely Easy 60-Minute Home Improvements
- 12 Sheds You Could Live (or Work) In
- Assembly Required: 15 DIY Kit Homes
- 30 Things Every Adult Should Know How to Do
- 10 Surprisingly Simple Woodworking Projects
- 7 Surprising Other Uses for Mayonnaise
- 9 Ways to Make Your TV Look at Home
- 9 Totally Amazing Mobile Home Makeovers
- 21 Ways to Spring Clean—Naturally
- Show Off: 9 Ways to Display a Collection
- The Best Paint Colors for Low-Light Rooms
- 7 Easy Budget-Friendly Backyard Makeovers
- 8 Clever Storage Solutions for Pots & Pans
- 8 Creative OTHER Ways to Use a Closet
- 12 Tiny Gardens to Grow on a Tabletop
- 15 Eye-Catching Front Door Options
- 12 Places You Never Clean—But Should!