The company I work for has decided to expand big time online and so bought up a lot of high ranking domains based around similar keywords.
The following is a bit complicated to put into words but here goes:
Two of these domains (call them ABC.com and BC.com) rank 1st and 2nd respectively for their keyphrases (which also happen to be their domain names: ABC and BC) Note: Doing a search for BC will also bring up ABC at about position 7 or 8 but searching for ABC will not bring up BC anywhere due to the amount of competition.
ABC.com is a fully fledged e-commerce site, doing pretty well. AB.com is nothing more than an info page but searches 2nd because of its age and domain name matching the search phrase. What we want to is actually take advantage of BC.com's ranking to create the income that we know would come from it. Because ABC and BC are basically the same thing (kind of like: plastic_red_blocks.com and red_blocks.com) we could take the easy way out and simply duplicate site ABC.com at BC.com but we hope there is an easier way to get visitors to our ABC.com site from BC.com whilst keeping BC's high google ranking.
We did wonder whether just duplicating the ABC homepage at BC and leaving each link on the page sending them to ABC would work, or would google spit-take and go 'nuh-uh, no way'?
If you use a 301, the two listings will probably be consolidated into one listing.
The same will probably happen if you duplicate the content (Google usually canonicalizes duplicate content pretty well).
If you really want to keep both spots in the SERPS, the best solution is to have unique content at each URL, and just put regular links pointing from one to the other. That's more work, but probably worth it.