The kind of cottage that Robert Ferrars professes to admire would be more like a cottage orné than where the Dashwoods live at Barton.

Another JA character, Sir Edward Denham in Sanditon, has similarily foolish ideas about cottages:

He is "running up a tasteful little cottage orné" on a strip of land at the seaside resort and likes to arrange 'viewing parties' to go and see it.

"I hope I can persuade you to perambulate as far as my precious little cottage orne, which is now so nearly finished that l prognosticate prevenient tenants. Your comments will be of such ineffable use. The cottage needs a woman's discrimination to tell me what is now lacking there."

Here is a note on them from an online book:
Jane Austen in the Garden Google books online

Here is a post (linked below) from the L&T archives explaining about the architect Bonomi, whose cottage plans Robert claims to have thrown into the fire.