Screw-in studs are very common on aftermarket racing axles. I have them on both my 9" swapped rears. I love em.
Also, some aftermarket axles come with both 4.5/4.75 patterns. Screw in studs makes changing patterns easy.
but they're bolts, not studs and Cass said he "can't put tapered bearings" on those axles with the 1.75 brakes.
An email from Cass
I stock A-body 5 x 4.5" bolt pattern axles for re-drilled 5 x 4" bolt pattern brake drums, but they are only available with Green bearings. $298 pair, assembled. They are not listed on my website. If you are interested, I can Email you an invoice and payment link. Tapered roller wheel bearings are available for A-body 8.75" axles that use stock B/E body drum brakes, though. Cass