@Brain:
No, all you will succeed in doing is making people buy only infantry.
Yes, if you are playing the classic MB 1984 edition, then people would buy infantry for sure.
Butt in this edition, you may only place like 4 new units in that territory. So with a 4 unit limit, will you still buy 4 infantry and save the rest, or spend all your money on Tanks ?
Or lets say your factory has been bombed, so you must spend 7 IPC before you can place your first unit. In this case your infantry will cost 10 IPC and your tank will cost 13 IPC. Not a very big difference any more, is it ? Lets say you got the money, do you really want a 10 IPC inf when you can get a 13 IPC tank ?
And when you need to move your army cross an ocean, a tranny only takes 2 units as cargo. So do you fill your trannies with weak infantry or strong tanks ?
I think that all the limits do favour purchases of more expensive and valuable units.