Here’s my perceived difference between metasearch and metasource: with metasearch, a site takes the results from several different engines and lays them out in one results page. With metasource, a site offers links/forms to several different search engines, and then either links directly to the engines for the results, or frames their pages of search results. That’s how I define the two. Your milage, of course, may vary.
Yurnet, at http://ww2.yurnet.com:8080/, is definitely metasource, but that’s not a bad thing. From the pull-down menu on the front page, Yurnet offers pointers to many search types including word definitions, image search, general search engines, and a variety of whois and DNS information (it’s a pretty eclectic set of stuff. Might be useful to break it across multiple pulldowns, maybe General Reference/Net Tools/Specialty Search.)
Yurnet sometimes kicks you to the results page of an external search engine (Alexa) and sometimes provides the search results itself (Web search.) And sometimes Yurnet will frame a couple of different search result pages side by side (natural language searching.) Enough of the search results are provided externally that I think this site is a metasource engine (though again that’s not a bad thing.)
In addition to the metasource Yurnet also offers an interesting comparison engine — pick up to three engines (out of a pretty large field) and get a page with up to three framed search result pages. I used it to compare the results of a search across three image engines.
Yurnet looks like a handy toolbox of specialty searches. I might add a few more to round them out, and organize them in a different way, but there’s a lot to use here. While you’re at the site check out the Toolbar (unfortunately IE is required) and the blog.