Well, it depends on your idea of inexpensive. Subconcepts in Roswell, NM sells Engel kits and they do indeed produce a Nautilus kit. However, it runs around $1500. Not bad really, if you consider it does include all the little stuff you need (sans radio equipment) to build it. I have purchased and built Engel kits in the past and am currently building a 1/48 Engel Gato fleet boat. They are not hard to build but do present challenges. Frank from Subconcepts is very helpful and a wealth of info. His website is
http://www.subconcepts.com They are revamping their website right now so it is a little tougher to navigate but still worth a look. As far as I know, Frank is the only importer of Engel kits in the US.
Hope that helps!
Best regards,
Pete Olson (AKA subsinker)
There are two types of ships: submarines and targets