Fighting Bob,
There are two other places I know of for Blakeslee Cartridge holders - one is BlockadeRunner.com; they sell their Blakeslee for I think $99.00, and the other is Taylor's, the importer of the Spencer, they sell. The cost for theirs is around $225.00, I think.
What I did, is order a cartridge belt with loops for just my Spencer. It also has a pouch for additional rounds.
When I go coyote hunting, now, I carry the Spencer (great in the woods of Miane) and plenty of ammo. If I don't see any coyotes, I do some target shooting, so it's not a lost day.
Two Flints