Is there a budget?
What's the turn around time?
We always design interior signs in the hundreds or thousands, so when we order a sample to show a client, we prepare for the sticker shock - sometimes in the $200-500.00 range depending on the complexity and the shop providing the sample is not making any money because of the thought it takes. Usually single semi-custom - custom office signs are a budget buster for most people. If you are going to use this as a piece to get you more work, be prepared to lose a chunk of your buttock - but it might be worth it - I would make 2 or 3 because the cost of the other samples would me minimal once you have the material.
Most office signs that look custom are still in the "stock" custom sign category.
Another thing, not all acrylics are created equal either.
http://www.3-form.com
Also, how you finish certain types of acrylic will change the perception of just being a plastic sign: for instance, second surface metallic paints, second surface digital prints/paint patterns, media blasted textures, inlays, even woodgrain print, then polished or eggshell edges.
Then creative use of backer materials like textured metals , stone, wood or embedded resins.
https://mozdesigns.com
or variations of -
https://www.takeform.net/galleries
Maybe even adding something dimensional - like a water-jet cut logo on backer with a changeable panel.
https://www.facebook.com/artsigns/photos/a.759328804130376/2011502718912972/?type=3&theater
Another thing is, and I think you know this was coming:
Once you identify a room, it becomes a code sign with braille and tactile required. Now, you can have the client sign off any liability on your end and put braille and tactile later if there is an issue... but consider this one thing. You can do one sweet complaint office sign that other business will see, to sell hundreds of compliant signs later. Either way, just thought it was worth mentioning.