Linksys ships the WRV54G, which offers up to 50 VPN connections in an office: This $230 device could replace much more expensive equipment for managing VPNs. It handles just the IPsec-over-L2TP method, as far as I can figure out from the extremely detailed user manual. It looks like just the ticket for an office that needs robust security without the complexity of managing a high-end server. This could transform the cost and politics of VPNs.
One fine device, however I got to say I do not find much functionality as a VPN concentrator since there is no IPSEC (tunnel to tunnel) cross-traffic capabilities. Branch A can not get to Branch B through this box at the main office.
It does not support Slit tunneling and do not offer tunnel (IPSEC session) on demand, on the contrary the tunnel comes up all the time as long as it is configured and the destination IP address configured is available.