First of all, I love this post. Second, I love this response.
It's true you can't ever get too much Filco. But, with that said, maybe try something different? You have a Filco TKL MX red, and an HHKB Pro 2 on the way. (which means you can actually stop collecting right now, you have the two best keyboards in the world.) But, to be thorough, maybe try ergodox? or other ergo-keyboard? Try Bucking Spring IBM-style keyboard? Or Alps switches? Or a Cherry ML switch keyboard?
In situations like this, I always think of the words of the inimitable Senator Phil Gramm, Republican of Texas, when he said (and I'm paraphrasing a bit): "I have all the [keyboards] I need, but not all the [keyboards] I want."