Where can you find different variations of the Remington model 4 rolling block rifle?

Have you tried the Remington Arms web-site? From the information that I have the Number 4 rolling block rifle was made in the following variations:

No. 4 Rolling Block Rifle, manufactured from 1890 to 1933 in .22 S-L-LR, .25 Stevens (barrel may be marked "25-10"), or .32 short or long rimfire calibers.

Cadet Model (pre-dates the Boy Scout Model) only manufactured from 1911 to 1912..........very rare

No. 4-S "Boy Scout Model" caliber .22 S-L-LR

No. 4-S Rolling Block Rifle Military (commonly marked "MILITARY MODEL") or "AMERICAN BOY SCOUT" which is also very rare. These were thought to have been used by military academies for training cadets.