Lower end? Not quite. The sky is the limit with OpenWRT (or the RAM is the limit I should say). They all start from the same source. SVEASOFT is nothing more than a slightly modified stock LinkSys firmware and I think the guy over there is an ungrateful GPL hating CeNsOrEd so I don't allow discussion of his customized versions here. Of course SVEASOFT like the stock LinkSys firmware is already running a web server, that's how the configuration web pages are served. On my OpenWRT router I actually have two different web servers running on it at the same time, neither are the stock versions. In fact one is even capable of PHP.
http://voidmain.is-a-geek.net:82/
To install a web server on OpenWRT it would be as simple as "ipkg install webserver" if "webserver" is the name of the server package you want to install. I would suggest that if you are interested in OpenWRT that you sign up on their forums though. My site is more for Linux based distributions, GPL and other related Open source that runs on Linux. Yes OpenWRT and other LinkSys firmware are Linux based but the people coming here for help don't seem to really care about that so I don't particularly like dealing with WRT54G issues here too much and sometimes regret writing the revival tip that seems to draw all the WRT54G people here.