hello..i've fllowed the same project
for what i'm aware of the only manufacture that offer 28mm late Sudan Egyptians is Essex:http://www.essexminiatures.co.uk/collections/25mm-colonial/products/co26
i own some and they 're OK ..
Also, If you refer, broadly, to Egyptian Army reforms ..the black sudanese infantrymen in later equipment and uniform are an essential part of the army for the reconquest of Sudan..and you've more choice: Old Glory; again Essex , Conoisseur (Bicorne), Bicorne..
at finally if you really want everything historically correct for te cavalry/mounted/dismounted camerl Corps...you have to look at Hincliffe (trough Hind figures) ..OG mounted Egyptians painted in kaki are also an option