The International Xenopus Genome Consortium (including groups from the US, Japan, France and the UK) have made several Xenopus genome assemblies, from the Rokhsar group, available to the public through Xenbase.
See: http://www.xenbase.org/entry/doNewsRead.do?id=136.Xenopus tropicalis v8.0 was generated using improved computational methods, incorporating additional BAC-end data and by integrating a dense genetic map resulting in a more contiguous assembly mapped to chromosomes with 50% of the contigs >72 kb in length.