I see 30" wall ovens put in lower cabinets under a cooktop all the time...even in magazines. You do what you have to so. I get it. I am having a hard time visualizing your plan, but I think it would be fine to have lower cabinets be wider than your upper cabinets. My sink will not be centered under the window.

My 3 uppers are not the same size. My range hood is 42" wide and range top is 36" wide. That leaves lower drawers different widths. Draw it out for us. Maybe someone can help.

I like your idea. It's a minor variation on the one I went with.

First off, a simple cooktop set into a solid sweep of horizontal counter gains you a whole bunch of visual organization and a very nice simplicity. Drawer stacks with drawers of one finish sweeping along in matched horizontal lines below that continue the organization and simplicity--regardless of the width of the drawers. I think it'd be kind of hard to goof this up enough to look bad.

Now, an oven does interrupt those under-counter lines, but well placed it will all still look good. If it's under the stovetop, appearing to be centered under the vent above the stove is far more important than what size it is. Fact is, a cooktop set into the counter simply isn't the driving feature a range is because it's not very visible. If you're using a look-at-me vent hood above it, that is what will focus attention.

As me how I know. :) We also have an L counter with stove and sink on it, and a work island. I designed a pleasant look-at-me wood hood, 42" wide, which with its display shelf is the feature that grabs attention when one looks into the kitchen.

To fit everything in on our L counter, we put a 30" drawer stack under the 36" cooktop. Does this look weird? No. When the topic's come up, most people hadn't noticed at all, some hadn't noticed before they finally did and commented on it.

BTW, I offset our oven to the side, where the island mostly blocks it from sight on first entering the kitchen. I thought it would look nicer to have the drawers one does see on the right end continue on across under the stove, which it does, and I thought I'd prefer not to have to stand in front of a hot oven to work or to block someone else's access unnecessarily, which I do.

Of course, for those who might have cared (not me), the oven's contrast with the cabinets surrounding it would have drawn some attention to the fact that it's narrower than the cooktop above it in a way that the rows of white drawer fronts don't. Not that I wouldn't have placed it there for that reason.

This sort of thing may be less common, but as long as the entire construct is visually balanced it'll make visual sense.

What would look odd would be if there were an obvious dysfunction involved. Discarding all the usual options for one that just can't work well does look odd and never comes off. Everyone who cooks notices--big time. Like doing without an oven and instead mounting a TV under the cooktop where no one could see it. That would look odd.

TV in place of an oven--an interesting idea since I hardly ever use an oven! I am spending way too much time trying to figure out where to put the silly thing. I toyed with the idea of moving it to the island so I could have an entire bank of drawers under the cooktop, but it messed with the island layout too much. I am attempting to upload a diagram of what I am trying to achieve (hopefully, I did not upload the entire contents of my hard drive).