When going with aftermarket shocks that arent designed for your brand of RC, sometimes modifications are needed to get a good fitment. If you do find shocks of similar length, the shock ends may not be a direct fit. That would be my biggest concern. Next up, spring rates. You do get a set of shocks that "bolt up" perfectly to your towers and arms, but finding out you have maxed out the the collars, and ride height is not what you expected...now you are on the search for new springs.
I'm not trying to deter you from your quest for better shocks. I'm just trying to forewarn of possible obstacles ahead when you see a set of shocks and the description/specs says something like ..."fits Brand X's Big Truck, or similar monster truck platform."
Do a Yahoo! shock upgrade search on your RC platform, and see what pops up.
Maybe look into one of eBay's chop shops for parted out shocks from a RTR platform.
I know, I'm not much help, but good luck!