Sitescooper.org offers a few sites that are scooped daily and converted into both Plucker and iSilo formats. You can simply download and install the appropriate file, no scooping required! Check it out at
http://scoops.sitescooper.org/. You can find a little more information about this service at
http://sitescooper.org/scoops.html.
Note also that the software that runs this automatic service is available for download as well. You can install it on your webserver (most will run perl) and modify it to work on whichever sites you like. It could be your own private (or public) scoop download center.