Add a node while editing another node?

Alright, I think this is simple enough, so let me know if I should try to do a better job of explaining myself:

I have a site where users input equipment they have for sale, so equipment is a content type. So, imagine a user in the midst of adding or editing a given equipment node. One of the fields in the form is a node reference field, a select list which is entitled "manufacturer" where the user selects the manufacturer of the piece of equipment. The nodes that are referenced are in a view which grabs all the manufacturers from the manufacturer content type.

I understand that I can add manufacturers simply by adding a manufacturer node.

However, my client wants users to be able to add manufacturers themselves, while in the midst of adding an equipment node.

I short, have I crippled myself with the way I've set this up such that I cannot add such a feature? What modifications would I need to make to my structure in order to allow for such functionality? Ideally it would be something like, the manufacturer field is really two fields: the select drop-down and a text entry. The text entry might say "other" or something, so that when an equipment node is submitted with something in the "other" manufacturer field, the db would be queried and if the entry for "other" is not already in the list of manufacturers, it would be added.

Please let me know what I can do, and if you need more detail.

Thanks very much,
-patrick