Hi, I saw one the other day that fits your description that I wish I'd put in my kitchen ideabook. Maybe one of these will help : https://www.houzz.com/photos/22nd-lower-modern-kitchen-san-francisco-phvw-vp~1120520

Emily, with being a renter, I'd definitely check Pinterest for temporary solutions. I've seen DIYs where you can starch fabric to walls with an iron. Also try temporary wall paper/decals, but I'd test a small area first. Cabinet makers or even yourself would be able to create a flush vanity without attaching it to the wall. Plywood, especially hoop pine, has received a lot of traction. It really gives a clean, organic look that you could have custom cut to fit in the area. You could also use it on the wall – it could be stained, left natural, or painted for a feature. Have a look at EchoPanel. It is a decorative, acoustic pinboard that would add a splash of color/design. If it is above your vanity, you could pin pictures, inspirations, etc.

Without seeing samples , I like the sound of the builders suggestion -- anything lighter in tone would be too wimpy IMO .

my suggestions keeps a small separate laundry with stacked washer dryer plus a bigger storage space for vacuum, ironing board etc adds a handbasin to the toilet and, using a round shower and curved back to wall bath allows space for a generous vanity ... the new kitchen has a pantry, stacked wall oven and microwave, double sink, dw and space for a 600 - 750 cooktop with floor space for a free standing central chopping block island ... the new location for the dining room allows for a window to the garden and sliding glass doors opening to a deck facing north to warm up the new dining room and kitchen ... there's a new window in the living room and the old back door is replaced with a window and i've added doors across the hallways to zone heating ...with careful choice of standard sized fixtures and fittings your budget should be ok but removing walls will be a big cost but well worth while for such great improvements to your home