if i understand your suggestion James, you're refering to Solr taking care of aggregation of searches across multiple seperate servers correct? you use the term "master solr query instance" but i assume you are refering to a SOlr server that is merging query results 9and not using the word "master" in the master/slave replication sense)
is that correct? i aggree, it would be a great feature, but it's very hard to get "right" ... particulararly when you start taking about some of hte complexities of hte SOlr RequestHandler interface. There has been a lot of brainstorming on the idea... http://wiki.apache.org/solr/FederatedSearch ...but no one has really come up with a clear direction on how to achieve the goals -Hoss