sys-apps/less can be built with the PCRE regex library, thus allowing searching with pcre patterns. The attachment is my patch to less-445.ebuild Reproducible: Always
Created attachment 291997 [details, diff] less-445.ebuild.diff
should be all set in less-445-r1 http://sources.gentoo.org/sys-apps/less/less-445-r1.ebuild?rev=1.1