All the long leadscrews, motor mounts, bearing blocks and delrin nuts I used to make and sell on eBay are now being made by my friends Scott & Wanda at Precision-CNC-Router!
If you don't find one listed in their store, send them an eMail and ask for one!
Tell them WidgitMaster (Eric) sent you!
They have NEMA 23 & 34 motor mounts machined from solid 6061-T6!
Eric