Several third party firmwares for the linksys wrt54g wireless AP + "router" (which, of course, is owned by brand C) implement sshd using dropbear. For example, the ones at sveasoft, and at h.vu.wifi-box.net
How do you know what you get in the box is the same as what was shipped from the factory? Or was it just re-sealed and put back on the shelf with an altered configuration?
http://www.securityfocus.com/archive/1/364977
If you buy your network equipment off Ebay, what are you really getting? Does it come with hitchhiking firmware pre-installed? The power of the Internet means the bad guys don't need to care who buys the tampered equipment, because it can "call home" and tell the bad guy where it ended up.
and, of course, there are no back doors in code directly from vendors, government standards (can you say clipper), ... [sounds of luftswineza] building from certifiable open source that has been inspected by many is the only half-credible scheme of which i am aware. randy