Microsoft Visio. Very basic but essentially to scale (despite my disclaimer). Easy way to send out to 3-4 companies for quotes. I did the research for cutouts and sourced the appliances myself.

You can probably get a free trial or subscription for a month for relatively cheap. Or if you have some ideas you can jot down and do a rough sketch on paper, I could certainly help draw it up and PDF. Wouldn't take long at all with the dims and information.
ETA: I posted a full thread on my construction process at the link below, if it helps anyone:
https://texags.com/forums/34/topics/3129853/replies/57127423