yeah the O-RC1 is a bit wider. I remember when I got my first F remote and how it looked like a couple sticks of gum stacked together. My first thought was "...I better order about 6 more of these because I WILL lose that thing..." And sure enough I started misplacing it while using the thing!
Don't have the same issue with the O-RC1 though I did just order a couple extra, so now I have one in each bag as well as another extra at home. I should never be hunting for a remote but I already know I will still look for them.
BTW, some universal remote controls, like for your TV and what not, will also activate your Pentax camera. I think there is a post somewhere in a thread here on PF. I remember reading it and found one of my remotes did work. Of course I forgot which one did and have no idea where that thread might be. The topic might have been for some software to use on your PDA that makes use of the PDA's IR transmitter to control the Pentax camera. Or it might have been in a thread discussing programming your HP calculator to do the same thing. If ya don't know some HP, and other, calculators have IR transceivers so they both transmit and receive. This can also be programmed. As I recall people were working on writing a program for the calculator to shoot time lapsed and/or long exposures.
So you might try hunting for either of those basic conversations. Wish I could be more help, but I'm sure you'll find it. I sort of like the idea of using a remote I would otherwise not use for anything as I also loose, or "accidentally" step on a remote because the TV or other device might be misbehaving and needs to see I am serious that it is close to the scrap heap, thus the remote becomes an active participant in ritual sacrifice.