Here is a short summary of Module factoring proposals :

Feature	R5RS	ModuleFactoringCowan	ModuleFactoringShinn	ModuleFactoringGleckler	ModuleFactoringMedernach
(scheme io)	base	base	(scheme io base)	(scheme io)	(scheme ports)
(scheme repl)	base	yes	no	yes	yes
case-lambda	SRFI 16	base	(scheme case-lambda)	(scheme case-lambda)	(scheme arguments case-lambda)
multiple values	base	base	(scheme multiple-values)	base	base
normalisation	none	(scheme char normalization)	(scheme char normalization)	(scheme char normalization)	(scheme char normalization)
package all io	base	no	(scheme io)	no	no
parameters	SRFI 39	base	base	base	(scheme parameters)
records	none	base	base	base	(scheme records srfi-9)
unicode	base	(scheme char)	(scheme char)	(scheme char)	(scheme char)