i also have the 260 gallon. I didn't build my own frame though i went ahead and got the one that comes with it. I don't think its to expensive...80 bucks for 6x6x3. if u got the same thing in wire it would be probably 300 or more. and they are machine washable. the only thing i found problems with is hanging stuff. you have to get creative but once you can figure out something to hang from the middle its not bad. My little guy did chew through his first one, but it lasted me 2 years. and i ended up just patching up the holes really easy. i only replaced it b/c my mom broke the zipper. i really like them.
An a helpful hint: to keep the bottom cleaner fold up a shower curtain (thick plastic) and wrap it around the bottom that way its just an easy sweep up of the food and a wipe down every morning. it keeps the smell down too b/c u don't have as much food stuck in the cage.