Please remember that many humane society's simply do not have the time to put all the animals on their website.
Plus many will use foster carers if they don't have adequate facilities on site.
The best place to start would be call or e-mail them and explain you are looking for a rabbit to pair with yours, and ask if they can recommend a responsible place or person to contact.
Additionally it looks like there are plenty of rabbit rescue places in Missouri.
Missouri Rabbit Rescue Groups
They may not be right on your doorstep, but a few hour round trip to make your own bunny happy, and offer a rescue animal a chance of a new life isn't unreasonable. The trip to collect our current male rabbit (to partner our bereaved doe) was 2 hours each way. Including the time spent when we collected him and started the bonding process onsite the whole day took over 6 hours, but was well, well worth it.
I know of members on here who have travelled much further than that to collected adopted pets too, so please don't let a slightly longer journey put you off.