The words "possible" and "practicable" are often confused and used in the same sentence.
While it is possible for nearly anything to be done in custom gunsmithing, this conversion you speak of has some serious practical limitations.
1. Most all available .22 LR lever actions use weak prop-up type locking mechanisms, entirely unsuited for a centerfire cartridge.
2. Actions and barrels, feed mechanisms, etc are designed around a given cartridge and it's dimensions. It's quite a leap to go from .22 LR to .32 H&R Magnum.
3. Action strength is designed around not only cartridge chamber pressures, but the backthrust or breechload placed on it. A .32 cartridge will produce 2 1/2 or 3 times the breech thrust of a .22 LR if chamber pressures are equal. That puts it out of the .22 LR strength category from the start. A very few lever actions produced in the last 140 years have been designed for rimfire/centerfire cartridges in the same caliber. The Marlin M1892 was one, and it was NOT a rousing sucess.
4. If you are determined to convert a rifle/carbine to .32 Magnum, start with something in .357 Magnum. I can recommend the Marlin 1894C, or even the Winchester M94.
A custom lever action is almost certain to cost a lot more than simply finding a Marlin .32 Magnum.
