The following link takes you to a site run and owned by a good friend and knife training partner Mike Sastre.
http://www.rivercitysheaths.com/
Tell Mike you know Brownie from Massachusetts and what you are looking for.
He makes custom kydex rigs for about anything that can be carried and has made several custom sheaths for me to hold some very exotic toys.
I'm sure he can hook you up with something concealable if thats what you are looking for.
I have two monadnock polycarbonate 1" diameter sticks in my collection. Carried one on duty for 9 years as it was police issue equipment [ though thinner than most LE monadnock sticks ].
After an hour of playing with these in the drills your forearms are about to fall off. You can also rip muscle/tendons in your wrists/forearms making strikes if not careful. These are waytoo heavy to weild in a fast paced defensive scenario.
I utilize the bamboo or wooden dowels in 1" format that are 26 inches long and these are weilded much faster [becoming a blurr] while in use.
The monadnock would take heavy glancing/defensive blows and survive better than the dowels or bamboo but they are just too heavy to be effective in a dynamic environment where you need to redirect your defensive moves directly into something offensive.
Everybody has their preference but the lightweight sticks are much betrer in my hands. I've played with both extensively and prefer the wooden dowels in 1" diameter.
Dumbbell training won't keep you from ripping ligament and tendons in the forearms and wrists. I suggest you try to take a few small hits with a partner delivering the blows on your person. You should get the feel for the stick quite quickly and know that the lighter stick causes quite enough damage to the ooponent when used in anger vs the partner just tapping you until you know that anything harder will injure you and require some sort of medical attention. It's the only way to know what you can deliver for punishment. Take some small hits and tell me the light stick won't "do" someone in a hurry.
As to the asps locking open, thats what I'm looking for. I don't want it collapsing on me at the most inopertune time. The yare easily collapsed after the threat has been nuetralized by punching the end of the asp onto a hard surface. If the asp didn't lock open it would be basically useless as a defensive tool. Thats how they were designed and thats how they perform, to lock open once expanded and stay that way until a concerted effort is made to retract itself by the operator.
Check with Mike Sastre at the link above. He can hook you up with what you want, custom made to your criteria.
Brownie