If you wan’t off the peg then I can’t offer much in the way of otgher suggestions, having said that most factory wheels with a decent number of spokes should be more than adequate stiffness wise but…
If you have genuine issues with wheel *flex due to you weight and/or power then I suggest you phone some local or not so local wheel builders and discuss requirements with them, they will be able to build you a suitable set of wheels, to your budget and needs**.
I’m also not convinced on the merits of a single aero wheel, especially on the back…
* rule out other things first, frame, skewers, other fault with your current wheels etc. it’s really not clear what you mean by a vibration, do you mean a resonant wobble/shimmy? rubbing on the brake blocks? something else?
** listen to them, they build hundreds or thousands of wheels for different uses, they have experience of what works and what doesn’t, too often people demand an incompatible set of requirements
ie: must be super strong, stiffest wheels ever, but want 8 spokes and <1300gm, and all for tuppence.
You should tailor your wheels to your needs, if you need super strong then look at heavier rims and lots of spokes, if you need super stiff then look at your spoke profile choices (and number) and hub flange diameter etc. weight may be the compromise, or if you must have super light then you will need to compromise elsewhere.