Houzz has a couple really nice vanities for sale: https://www.houzz.com/products/bath-products-pcat-br~t_468

They are not custom, but may have the price tag of something custom. They are all-wood construction. If it's a bit too expensive, you should check out a kitchen and bath show room near you and talk options with them.

Look at the Cabinets to Go website for vanities that are reasonably priced. Also check into converting existing furniture into vanities.
https://www.houzz.com/photos/furniture-converted-to-bathroom-vanity-phbr0lbl-bl~l_48649

Woodpro makes beautiful cabinets and their Royale line is more reasonably priced, they are made in America and real wood too!

Hi! Here are a few that you may consider (I have included a few single and double):

http://deciture.com/shop/furniture/7/reflections-single-vanity/

http://deciture.com/shop/furniture/7/manor-house-double-wide-vanity/

http://deciture.com/shop/furniture/7/provence-double-sink-vanity/

http://deciture.com/shop/furniture/7/hamilton-49w-shutter-bath-vanity/

I don't know if you are local in our area or not but Waypoint Living Spaces is a brand of cabinets that we carry. They are made here in the US (locally too) are made of real wood and they are reasonably priced with lots of options! Please contact us if there is anything we can help you with!