Unfortunately not. There were some awesome Quick Codes out there to modify staff, I used them when they were released to upgrade all staff to S++. There were also resource codes that I used to max out all resources, static weapons and vehicles.

There were no codes that accelerated weapon development, however.

Alas, all this is now irrelevant as Save Wizard have removed Advanced Mode from MGS, so we're all restricted to the GMP code that's currently available. Shame, as there was a lot of activity around resource codes and staff codes that looked really promising. I suspect I'm in the same boat as you now, griding out the offline weapons that take over a week eslapsed to develop!