You mean like the little nipples on the j and f keys? or h and g?

What you really need is a 3d printed "custom" xkeys shell / cherry keypad deal. Sort of like a custom Ergodex but made specifically for you and with non changeable key caps.

You could probably produce one for about $300 if you know how to design in CAD. ABS plastic rapid prototypes run about $5 - $10 per cubic inch plus setup fees at a 3d printing service company.