Apologies if you have already considered this, but with a shelf vanity, if the sink does not sit on top of the shelf, then the sink will start at the counter, and go below the shelf. Its a design consideration (your right hand photo shows it ) -- what do you want visible -- plumbing wise. The depth of the vanity shelf front may need to be adjusted so that the bottom of the sink and the plumbing does not show, or plumbing is selected that is attractive. The cottage-y example has a deeper front on it to hide the sink bottoms. Benjesbride has an excellent point about keeping stuff on shelves clean -- it will take a lot of cleaning to not continually collect dust (it'll show on the shelving, and be embedded in the towels...dust, splashes, etc.). Good luck!

it would help if you posted a pic of where this is going, and why you want a left offset w/such a long vanity. you can find a 60", but a 67" is an off size, you may have to go custom. I did find this one at 67" Or, do a 36 or 48" vanity, and just continue the countertop over to the right with underneath supports or something like this ignore the mirror, but do a simple 36" vanity, continue the countertop over to the other wall (or just end it) and do a support in the middle or agains the other wall. You get your own countertop made for the vanity and the extension (like you would for a kitchen)

Ikea vanity looks really nice. Thanks for sharing. We looked at vanities from Wayfair, AllModern, Ikea, etc., but opted to work with a local woodworker. It felt good to support a neighborhood artisan. When we come up for air we'll have him craft built-ins and purchased add'l Walnut with that in mind. At this point the Brio valves are roughed in for the shower and wall mount lav faucet so there's no turning back. To clarify, my question is when pairing an undermount sink with a wall mounted faucet and 24x20 countertop for use in a master bath - what's the most functional shape or is there no discernible difference?

How did this happen? Clearly the plumber did not have the correct centerlines and plumbed the sinks in the wrong spots. This should have been caught at the drawing stage, assuming you had the vanity you wanted from the beginning. If you purchased the vanity afterwards, then you should have made sure the cabinet centerlines were aligned with the faucets. Water under the bridge, however. I don't think you can re-plumb without tearing out the cabinet and the wall tile. So take the suggestion above of getting rectangular mirrors that are centered on the sinks.