Sure, but....
You sure can, but let's do the math here...
A. By the time you buy some 16" steel rims (Used I assume) and ensure they match the bolt pattern, and are in good shape, i.e no dents, bad rust, etc, etc. etc. ...
B. Locate, buy, have mounted and balanced some 16" "Skinny" and taller (I assume snow tires, not all season tires) on those lovely looking steel rims...
C. Gotta get some hub caps from wally world, as no one would promote the existence of a gorgeous CX-7 running around anywhere on earth on plain steel rims... that's just plain ugly.
D. ...and now they are on your CX-7,.. I can speak from 32 years of driving experience, no tire will match the proper driving speed, driving habits, luck and simple TREAD DEPTH when it comes to snow. I've had expensive SNOW TIRES on a 4X4 SUV (In 4X4 mode) and slid off the road. There is ONLY two factors in snow driving... talent / experience and tread depth. Above that comes chains, studded tires, etc. etc.
E. With all the above math, my $.02 worth of advice is.... keep your 17" rims, go buy some snow tires, have them mounted and balanced, when 18 March rolls around, take them off and save them for December 19th next year. (Dates vary by region you live in).
PRO: No need to store both RIMS and TIRES in the garage, but that's your call.
CON: You will have to pay to have them mounted and balanced twice a year.
PRO: you'll save miles on both sets of tires.
CON: No guarantee ANY tire or rim is going to help you get around in the snow.
PRO: You can report back to us here and tell us what IF ANY difference it makes.
CON: Time and time is money.
PRO: If you're a DO IT YOURSELF guy / gal, you can put on the snow tires in your own garage as you like, and vice versa as you like (take em off whenever you want).
Good luck!!
Peace!