bigloo : Bigloo is a Scheme implementation ( http://www-sop.inria.fr/indes/fp/Bigloo/bigloo.html )
c-wrapper : Foreign function interface for C and Objective-C libraries ( http://www.koguro.net/prog/c-wrapper/ )
chicken : Chicken is a Scheme interpreter and native Scheme to C compiler ( http://www.call-cc.org/ )
elk : Scheme implementation designed to be embeddable extension to C/C++ applications ( http://sam.zoy.org/elk )
escm : escm - Embedded Scheme Processor ( http://practical-scheme.net/vault/escm.html )
gambit : Gambit-C is a native Scheme to C compiler and interpreter ( http://www.iro.umontreal.ca/~gambit/ )
gauche : A Unix system friendly Scheme Interpreter ( http://practical-scheme.net/gauche/ )
gauche-cdb : CDB binding for Gauche ( http://sourceforge.jp/projects/gauche/ )
gauche-gl : OpenGL binding for Gauche ( http://practical-scheme.net/gauche/ )
gauche-gtk : GTK2 binding for Gauche ( http://practical-scheme.net/gauche/ )
gauche-kakasi : Kakasi binding for Gauche ( http://gauche.sf.net/ )
gauche-qdbm : QDBM binding for Gauche ( http://sourceforge.jp/projects/gauche/ )
goosh : Small process-control library for Guile ( http://arglist.com/guile/ )
greg : Testing-Framework for guile ( http://gna.org/projects/greg/ )
guile : GNU Ubiquitous Intelligent Language for Extensions ( https://www.gnu.org/software/guile/ )
guile-cairo : Wraps the Cairo graphics library for Guile Scheme ( http://www.nongnu.org/guile-cairo/ )
guile-gnome-platform : Guile Scheme code that wraps the GNOME developer platform ( https://www.gnu.org/software/guile-gnome/ )
guile-gui : Guile Scheme code that aims to implement a graphical user interface ( http://www.ossau.uklinux.net/guile/ )
guile-lib : An accumulation place for pure-scheme Guile modules ( http://www.nongnu.org/guile-lib/ )
guile-www : Guile Scheme modules to facilitate HTTP, URL and CGI programming ( http://www.nongnu.org/guile-www/ )
hop : Hop is a higher-order language for programming interactive web applications ( http://hop.inria.fr/ )
ikarus : A free optimizing incremental native-code compiler for R6RS Scheme ( http://ikarus-scheme.org/ )
jscheme : JScheme is a dialect of Scheme with a very simple interface to Java, called the Javadot notation ( http://jscheme.sourceforge.net/jscheme/main.html )
kawa : Kawa, the Java-based Scheme system and Language Framework ( https://www.gnu.org/software/kawa/ )
net-http : Library for doing HTTP client-side programming in Guile ( http://evan.prodromou.name/software/net-http/ )
racket : Racket is a general-purpose programming language with strong support for domain-specific languages ( http://racket-lang.org/ )
scheme48 : Scheme48 is an implementation of the Scheme Programming Language ( http://www.s48.org/ )
schemik : High-level lexically-scoped implicitly-parallel dialect of Scheme and Common LISP ( http://schemik.sourceforge.net/ )
schoca : Schoca is a Scheme implementation in OCaml ( http://sourceforge.net/projects/chesslib/ )
scm : SCM is a Scheme implementation from the author of slib ( http://swiss.csail.mit.edu/~jaffer/SCM )
scmxlate : Scmxlate is a configuration tool for software packages written in Scheme ( http://www.ccs.neu.edu/home/dorai/scmxlate/scmxlate.html )
sigscheme : SigScheme is an R5RS Scheme interpreter for embedded use ( https://code.google.com/p/sigscheme/ )
slib : library providing functions for Scheme implementations ( http://swiss.csail.mit.edu/~jaffer/SLIB )
stalin : An aggressively optimizing Scheme compiler ( http://community.schemewiki.org/?Stalin )
stklos : fast and light Scheme implementation ( http://www.stklos.net )
termite : Erlang-style concurrency for Gambit Scheme ( https://code.google.com/p/termite/ )
tinyscheme : Lightweight scheme interpreter ( http://tinyscheme.sourceforge.net )
ypsilon : R6RS-compliant Scheme implementation for real-time applications ( https://code.google.com/p/ypsilon/ )
Add an ebuild in portage :
The ebuild is now in the portage tree.
You can also use layman : emerge layman then layman -a gentoo
For Paludis use this rsync : rsync://gentoo.zugaina.org/gentoo-portage
If you have a problem : ycarus(-at-)zugaina.org