USB Keyboards & Arcade Sticks?

I'm getting a Dreamcast soon and will be installing a GDEMU. I really want to play more Third Strike and Typing of the Dead, but it appears the only way to use my fight stick & keyboard is with a Brook Wingman SD Converter.

However, this thing is not for sale anywhere online and Brook themselves told me that it's been discontinued.

I really don't want to buy a new original fight stick or keyboard... Are there any alternatives to using them on the Dreamcast?