THE MUSEUM - a realtime 3d art-gallery level that can be customized to include a total of 10-15 photos selected by the buyer,
and delivered as .APK or .EXE application playable on Android or Windows (respectively)

The initial source level exists in Unity and although the idea has some potential, I've yet to see anyone order it even at the ridiculous low price it's currently set to.

There are two other options for those who want a custom 3d level fully built from scratch, either based on a real location of sentimental value, or based on a loose pencil sketch or rough set of ideas. Either way, I will allocate twelve hours to the work, which means the time comes out to under $3/hour and sometimes well under $2/hr during sales. But nobody hires me to do that yet. They'd rather pay $5-7/hour for poster prints?

All of these exist as listings on my Etsy shop. For whatever reason, nobody has ever ordered, much less reviewed them. It's been a disappointing thing.
Ads on and other websites run by Matthew Hornbostel, include banner ads from Comic Ad Network [top ad - an unfiltered banner rotation system predominantly used by web comics, art sites, but occasionally some questionable items.] and my own banner rotation system [bottom - anything here is either my own stuff like websites, online shops, or social media profiles, or has been vetted by me and found to be generally legit. I have several cashback sites [all of them are ones I've used and cashed out tens of $ from successfully already] and major online retail stores [Sony, Microsoft, Amazon...] in that mix. Usually they give me some sort of small compensation if you buy from them through the link, which I'm disclosing right now. They're all legit spots, but if skeptical do your own research before committing to anything.]