Where could I obtain...a suitable 28mm Conquistador leader/general?

[Etranger]

The Eureka foot officers, from their Conquistador and Colonial Portuguese ranges. http://eurekamin.com.au/index.php?cPath=87_126 Portuguese are in the 16th century and later group.

[Nic]

If you are contacting us, I can supply pikes and crossbows at the same time.
Nic EUREKA MINIATURES

[Paul Richardson]

Gringo 40's have some nice figures, although their Cortez figure is on foot.

[Von Trinkenessen]

For mounted try:
Gringo 40's
Gamezone ( fantasy but spanish styled)
TAG
Casting Room @ Foundry
Eureka
Warlord wars of religion spanish commander (may be too late date wise? )

xbowmen:
Eureka
Casting Room
TAG
Gringo 40's

[Orctrader]

Thanks.  Plenty of options there.   

If you are contacting us, I can supply pikes and crossbows at the same time.
Nic EUREKA MINIATURES

Thank you very much but I'm in the UK so shipping costs are prohibitive.  I buy your stuff from "Fighting 15s."  Though I see they don't carry the mounted general.