Sorry for the delay on the reply, Bil, I was tied up with other things
yesterday...

>> (1) a web page with a text area prepopulated with a YAML template--the
>> user simply types in the values that they want to input; and
>
> I don't quiet understand this.  Is this a single text box pre-populated
> with yaml text or something else?

Yes, that's what I meant...

>> (2) a Ruby script that takes the POST, validates the input, generates
>> the output file, and passes that file to the real consumer of the
>> information.
>
> A fun job for Camping, or is that overkill due to lack of
> database?

I think it will be easy and fun to do.  YAML is just so simple to
create and process, and although I don't know anything about USM3D, I
suspect that it won't be too hard to transform the input to that form.

> Actually, we already have that in the form of a Fortran namelist,
> which is actually quite similar to YAML for this simple data, but
> some folks want a web interface that provides some suggested ranges
> and has some logic checking behind the scenes.

I understand better now what you're looking for.  In that case, my
suggestion would simply be to improve the UI with better elements
(slider, radios, auto completing fields, etc.) which means using
something like Prototype to do AJAX programming.

I hope that helps, Bil, and best regards,

Julian I. Kamil <julian.kamil / gmail.com>
http://pandora.rubyveil.com/ - Pandora Publisher
http://books.rubyveil.com/ - The Ruby Bookshelf