Here are some ideas that would interest me:
Switch-barrel rifles:
e.g. Martini .22LR and .22 Magnum
Take-down rifles, perhaps even with multiple barrel sets (Notice a pattern here)
Stalking rifles (How about take-down switch barrel ones)
Quick-detach scopes, such as claw mounts, EAW swing mounts, Kreighoff slide-off mounts
Making fitted takedown gun cases. I've made a few in my time and may have a few in-process photos. I have one in the works now for a two-barrel shotgun.
Hi Vol423, I'd really be interested to see some photos of your gun cases. I'm currently working on a Martini Cadet ELW takedown in an altered takedown shotgun case and could use some ideas.
How about a takedown switch-bbl in 17 HM2 or HMR, 22LR or 22WMR, 219 Zipper, 25-35, 7-30 Waters, 30-30 and 35/30-30? The RFs can be used with offset bores to allow the CF firing pin to strike the RF edge while the 30-30-size extractor will extract the RF cases adequately from the offset bore.
My Martini Cadet has a quarter-rib with QD Kimber rings to facilitate the takedown, will show pics when closer to completion. These rings return to zero within 0.5 MOA and are quite svelte, providing a pleasing appearance along with their superior functionality.
Meanwhile welcome to the site and don't hesitate to contribute!
Regards, Joe