Broken in but none the worse for wear, Bootstrap and less distressed companion Bootstrap Alternate each have OpenType features that automatically substitute a unique pair of characters when any upper or lower case letter is keyed twice in a row, as well as features for Old Style Numerals and Small Caps.
Bootstrap ls also available as part of the Vintage Wood Type Classics set, bundled with the complete Applewood and Buckboard families for $79 https://youworkforthem.com/font/T5313/aerotype-vintage-wood-type-classics
