I guess it's more about the budget then the content. Developers and designers are expensive and a good theme isn't build in 1 or 2 hrs.
The best would be to customize an already existing theme from the Marketplace.
I imagine theme developers are always looking for inspiration for their next creation. If you provided screen shots showing theme aspects, and colors you are looking for (most people react more favorably to visual cues then the written word) one of them might consider creating and releasing it if they think they can sell enough copies to make it financially worthwhile. A quote for a one-off theme will likely be "much" more than you mentioned above.
Please note that not all of the theme designers may track this forum so you might consider reaching out to them directly.
Things that would further customize the site for your unique needs would have to be done separately at additional cost by the theme developer or someone else skilled in graphics design. You might consider reaching out to your membership for graphic design help as one of them may have the requisite skills and might be willing to lend a hand for free or at a reduced cost.
A one-time fee will get you a theme that will work for any particular build that IPS releases. If you check out this link: Theme Differences - Invision Community you will see that they change things quite regularly requiring a theme designer to release updates pretty regularly. They will of course expect to be compensated for their time making requisite changes to their themes which they will expect to be financially compensated for. The price goes down as the purchase quantity goes up.
Creating an Android 12 Material Design inspired theme sounds intriguing, it's something I might be interested in.
Is there a known issue with Website/Service Down or Unresponsive errors popping up for AdminCP/Forum for Firefox, Chrome, Brave, Edge, & VPN connections on ChromeOS/Android?
Tried different connection types and basic browser/device troubleshooting, was wondering if IPS is down for multiple people or just me breaking something....again.
I like to experiment and learn new things. If I break it, I just start over, but I like setting up my own stuff. Amazon is good, but I want to do it myself.