Thanks for the Links.
I'm leaning towards a G15.
I can get one around $200; it's the right size and heft and I can use the live video preview for precise pre-focusing.
My plan is to create a script to run focus bracketing across a depth-of-field of about 40-50 mm, at 1 mm intervals (exact settings tbd).
FWIW, this is the work-flow model:
1. position item, camera, lights.
2. focus camera on closest point of item.
3. manually set TV & AV (ISO preset to 100, file set to RAW)
4. run script, capturing 40-50 images.
5. import images into LightRoom, discarding excess frames.
6. crop and adjust image 1, then copy adjustments to the rest of the images.
7. import adjusted images into Helicon Focus, save deep image and open image in Photoshop for touchup.
Rinse and repeat.