At kazim's suggestion, I have set up an rsync server to make it easier to download updated development ISOs.
This will make it so when a new devel ISO comes out, you don't have to download the whole file--just changed bits between the ISO you have and the new one. Cool, eh?
It can also be used for easy mirroring of the whole or parts of the blag archive.
I documented it here:
If there's something incorrect, please edit the wiki.
Let me know if it works for you.
Be sure to MD5SUM the files to make sure they're cool.