To further this idea, comparing it to DNSBLs is appropriate. There are a lot of DSNBLs you can use. Many agree that sbl-xbl spamhaus lists are high quality with no (or almost no) false positives. For that reason, a lot of us use them to block e-mail.
Bl.spamcop.net is another DNSBL, and while it's a fine list, the FP rate is much too high for me to block e-mail on it alone. However, it's highly useful in SpamAssassin, putting many messages over the spam score threshold.
While the SURBL staff has decided that they would rather not "divide their efforts" to support a project like this, it certainly doesn't mean that it shouldn't be done be someone else. At that point, the staff is right to ask that the discussion about its details be moved off this list. Perhaps the better place to discuss this is the SA general list as they are more open to just about any new project that helps SA detect spam accurately.
I know if I relied totally on any one method of filtering spam, a lot of spam would be getting through that isn't. It's because the comination of content and structure analysis with bayesian analysis DNSBL and URIBL all contributes to the end result.
Bret