I went down a path similar to this. Unfortunately, custom stuff often ends up as prohibitively expensive. I got so far as to talking to a couple of local seamstress/upholsterers and it came down to the fact that they value their time and the construction looked to be fairly labor intensive. Two basic rectangular boxes (think something like the Front Runner Flatpack boxes, but with different dimensions) was going to be several hundred dollars, plus materials. This makes your eyeballs pop, but after breaking down the project, it came down to a "shop rate" of less than $13/hr, which isn't much for skilled labor.
Instead, I did much better by keeping handy notes of all the critical dimensions I needed and doing a ton of searching. Google, Amazon, eBay, Container Store, and on and on. I eventually found containers that fit all the odd spaces I wanted to fill. Total cost about $60-$80 (some things were on clearance or otherwise "specially" priced). The only negative is that I don't have that fancy "matched luggage" look. Lots of disparate colors and finishes, but you can't beat the economies of scale when it comes to hitting a price point.
The other option is DIY. After going down the path of carefully specifying what I want for the sewers I talked to, I'm fairly certain I could build in about 40-50 hours what they quoted to build in 20-30 hours. I'm an amateur sewer at best, but my time is cheap, especially for activities I can do at night after the kid is asleep, etc.
