Linksys tends to be "leaky" with data about unannounced products. It also, like most other consumer networking companies, releases new versions of its products (mostly wireless) without fanfare. I occasionally troll for signs of these "stealth" products and my latest excursions turned up quite a few.
It looks like Linksys will be joining D-Link and ASUS in releasing a router with built-in gigabit Ethernet switch. However given its styling, model number, and pricing that I was able to find, the RV0041 looks like it's aimed more at small businesses than consumers.
Like other members of the "RV" line, the RV0041 can act as an IPsec VPN endpoint and supports up to 50 tunnels. In addition to the built-in 4 port 10/100/1000 switch, it also has a miniGBIC slot that can accept a 100Mbps (!) fiber module for alternate WAN connection. Surprisingly, the gigabit switch doesn't appear to support jumbo frames. Street pricing looks to be between $225 and $250.
To help get hooked up the the RV0041, it looks like Linksys plans to release the PCM1000 Gigabit Notebook adapter and USB1000 Gigabit USB adapter at street pricing of about $50 and $60 respectively.
Since Linksys released the new WRTP54G wireless VoIP router as part of its "G for Free" offer with Vonage, why not a wired-only version? The RTP300 Broadband Router with 2 Phone Ports seems to be the answer to that question. Although it doesn't look like it's being offered in any VoIP bundles yet, the product description mentions Vonage.
RTP300 Broadband Router with 2 Phone Ports
Neither detailed specs nor a user manual are posted yet. But the info that is available says the RTP300 has a four port 10/100 switch vs. the 3 ports in the RT31P2, which the RTP300 probably replaces.