This is an image from an old edition of Liturgical Arts Quarterly, of a Carmel in New York City. I am unsure if the building still stands, though I wonder if it has some connection to the complex in the Bronx occupied by the Sisters of Life at present. There is nothing necessarily earth-shakingly important about this particular space but it shows a handsome use of space, materials and form in a comparatively humble context. "Noble Simplicity," it is important to understand, was first used in an art-historical context by Winckelmann, the great apologist for Greek architecture, and had less to do with minimalism than a unity of physical form and concept, which I think can be seen here to a certain extent. If you look at this example, actual ornment is kept to a comparative minimum save sculpture; the windows are just rectangles. Yet a sense of scale and texture is preserved through the use of bricks, brick patterns and brick edging, such as around the sanctuary arch.
Some aspects of the design are not really cost-effective in a modern context--the curved wooden ceiling is quite elaborate, but a simple plaster vault treated in the right way could actually be quite handsome, and the large stone Calvary could be replaced with a simple brocade dossal and tester if necessary. Another important aspect is the care taken to ensure liturgical authenticity in the simple altar, fully-veiled tabernacle and candlesticks--the true integration of form and function. Another thing to consider is that where there is ornamentation and sculpture, it is deployed carefully; rather than wasting money on a surfeit of catalog purchases, the sisters appear to have stewarded their resources wisely and commissioned a small number of good-quality religious art suited to the structure rather than strewing a dozen bad-quality plaster Madonnas all over the interior without much rhyme or reason.
This is an important lesson. Many parishes will be considering retrofitting their 1960s churches in the next few decades; not all will be able to afford elaborate renovations. Rather than superficially trying to Catholicze their interiors with "badges" chosen for their mental associations rather than artistic worth (Mary and Joseph shrines of an indifferent 19th century quality bought from a closed Ruritanian ethnic parish in southern North Dakota), better to invest in a few original works by a classically-trained liturgical artist or sculptor able to draw out some virtue from an otherwise problematic interior. (I amaze myself that I am usually able to think of at least one good feature to highlight even in the worst interiors. The trick is to think like Bernini and find a way to build the entire composition around the one flaw you can't change, and make it into a virtue). At the very least, you will create more beauty rather than simply moving existing resources around.