That's the wonderful thing about AC... though it may take a couple days for responses to build, you are more likely to get more accurate reflections of what to expect from just about anything fish related. I remember doing my research on Clown Loaches before I got them... spent probably 30-40 hours researching just them. I couldn't tell you how many different sources gave such a wide range of sizes for them... and until I started seeing pictures and eventually in person, I'd never have known just how huge they can get. Its simply amazing to watch a school of 12+ clowns, each exceeding a foot in length, interacting and playing. They're an amazing species of fish.
There are lots of different loaches with different requirements too, so its not impossible to enjoy having loaches in a smaller (under 100 gallons) tank. I'm glad you're planning to upgrade, as I'm sure you're realizing, these graceful fish will require quite the large habitat once they begin to grow. Albeit, they are slow growers, but they do still need the space to grow into. If you want to see a fun little group of loaches playing and interacting, but want to be able to keep them in the 29, I'd recommend going for kuhli loaches. (especially the orange banded ones) They're a lot of fun to watch, and with a 29g tank and a few mid-upper level inhabitants, you could probably have 8-10 of them.
