"May I ask where do you source those 2824-2 rolex 1680 cases?"
The 1680 cases mentioned above are all for rlx 15xx date size movements or ETA 2836. I can not remember seeing any vintage rlx 1680 type cases made for Eta 2824. All the vintage type cases In my experience were made for ETA 2836 or DG/NN 2813 type movements.
ETA 2824 movements also have lower canon pinions, hour wheels, and sweep second posts and this can cause the hands to be too close to the dial on many projects.
Otoh if you made a typo and meant to say: "where do you source those 2836-2 rolex 1680 cases", the 'Paul' (Abay) cases have been gone from the market for 10 years. A few members may have one they might sell.
Be sure to read up on them because although they have the correct case tube threads and will accept oem crystals and bezels, the case back gasket is in the case, not in the case back like genuine watches. The crown guards need work and the lug holes need to be drilled out too.
"I have been looking for one that takes 15xx date movement (for a budget build) as it should assumably have a gen crown/stem/tune height position as well."
As stated above, most cases that will accept an ETA 2836 will accept a rlx 15xx date movement...not a no date movement. Imho the crown position is a very minor consideration especially on a budget project. Very few notice the crown position.