I know you said you didn't want to build one, but it was the only way for me.
Here's a pic of the shelf system I built, custom built to fit Tamiya paints, and the bookcase I use as a main storage area. The pic is an older one and I have twice the paints on it now!
The shelf is organized gloss on the left, flat on the right with a space left between to seperate them. Each tier can hold 23 bottles and there are 7 tiers, thats space for 161 bottles of paint. I could have pushed the width to fit another bottle per tier for 168 total bottles, but I wanted a place to store sandpaper (that's what is jammed into place on the right side), besides Tamiya only makes 33 gloss and 55 flat for a total of 88!
Don't look too closely at the mess below the paint shelf. this is a work in progress!
International Hobby lists the
Humbrol Rack, but there is no picture and it's not currently in stock.
MicroMark has the
Model 80 Carousel which might work for you.
Good Luck!