I've built a search engine for people that want to make there BTSync keys publicly available. You can search the site and if you have my browser plugin installed then you can just click the link and it will sync to you computer. I can't currently handle limiting large files or sync specific files but it might get most of what your looking for. https://www.meshedsites.com.
I built this site (MeshedSites.com) that makes accessing BtSync decentralized websites easy. You need to install my XTTP Firefox plugin and BTSync. After these are installed going to a decentralized site is similar to any other web site only instead of going to https://www.meshedsites.com you go to xttp://www.meshedsites.com. MeshedSites.com lets users create easy to remember aliases to their BTSync read only keys. We have also developed Waves which is a blogging platorm for the decentralized sites. Other projects are in the works. Check it out and let me know what you think. https://www.meshedsites.com http://github.com/NextWaves/waves