Looking for a monospace typeface with a smaller (regular?) x-height

Different type families are going to have different x-height size relationships with the capital letter height. There is no such thing as a hard standard for that. Type designers will make their own choices on how their glyphs will fit within an Em square. The person who designed the Georgia typeface (Matthew Carter) made different choices than Howard "Bud" Kettler, the guy who designed Courier.

If you dig deeper and open these fonts in type design apps, such as FontLab Studio, the physical cap heights and x-heights of letters are often different from the boundaries set in the font’s dimensions (it’s a really common feature with script typefaces). That’s one of the things that makes it really tricky to size and position letters according to their physical cap letter size -something I often do with sign design. It’s not enough to tell an app like Adobe Illustrator to use the distance from baseline to a font’s defined cap height line. The treatment might work for Helvetica Now, but it won’t work for many other typefaces. The same thing goes for the font’s defined x-height line.