Here are some of my plants which are in the magnimamma family. They have flowered already this year, so my apologies for not having taken them earlier.
Mammillaria rioverdense Rep 1123

Mammillaria bucareliensis multiflora Rep 355a, a young plant.

Mammillaria saxicola Rep 1139

Mammillaria vagaspina ML571

Mammillaria magnimamma PM34

Mammillaria preissnitziii ML072

Mammillaria preissnitzii Rep 1134

Mammillaria magnimamma PH403.1 (from Teotihuacan, Hidalgo)

Mammillaria magnimamma CD05/01 (from Peña del Aire, Hidalgo)

Mammillaria seitziana Rep 1950

Mammillaria seitziana v. tolantogensis Rep 1689

Mammillaria vallensis Rep R1117

Mammillaria vallensis v. brevispina Rep 1119

Mammillaria magnimamma PN085 (from Magdalena, Hidalgo - very close to the CD0501 above)

Mammillaria sp. Rep 1226 - this field number is from Zacatecas, so it must be wrongly labelled, but I'm pretty sure it is a magnimamma form!

Mammillaria magnimamma SB365

Mammillaria centricirrha Lau 1218

Mammillaria seitziana Rep 1109

Mammillaria krameri

And also a few photos from habitat in Hidalgo:
First M. magnimamma on a hillside just north of Pachuca

M. magnimamma near Atotonilco, Hidalgo

M. magnimamma near Venados, Hidalgo

M. magnimamma near Eloxochitlan, Hidalgo

M. magnimamma at the same site near Eloxochitlan - single headed and much bigger.

M. magnimamma at Pena del Aire, near San Miguel Regla, Hidalgo

This plant is the mother plant of the M. magnimamma CD0501 shown earlier in this thread.