I like to tie my own keepers onto hook shanks. I do this for most of my keeper needs. I'd like to find some bulk flipping hooks with no keepers. I know that Trokar has their saltwater straight shank hooks, but they dull very quickly. Brands like Owner make a weak flipping hook, and I like to snell my hooks, so the Twistlock design is not an option. I know that a Siwash hook is PERFECT, except that the eye is way too big and its not welded.

 

Do I have any other options?

VMC makes a closed eye siwash that might work and Damiki makes a straight shank called viper that would work.  Mustad HAS to have one available but it is probably buried deep in their catalog, calling someone like captain hooks would probably get you to the answer faster and since you want bulk your probably at the right place anyway.  Also, spinnerbait hooks would probably work although I doubt you will find one with a welded eye (if you snell do you really need a welded eye?).

Siwash Hooks, Closed Eye 

 

http://www.gamakatsu.com/fishing-hooks.php?pid=1232

I'm not sure where you got the info that the Owner 3X straight shank hook is weak but it's totally untrue. I also tie my own keepers and I've never had a single problem with the hooks strength. As to the other criteria you mentioned, bulk packs and welded eye, I'm no help with either of those. I really like the idea and design of the keeper that's on the Mustad Grip Pin Max flipping hook but I'm not sure where you might be able to purchase them in bulk. I know you said you liked to tie your own keepers but the ones already on the Mustad are, IMHO, the best design out right now.

 

If you haven't already I'd give the Owner 3X hook a try if you like Owner's cutting point, they're really good hooks in my opinion.