Increase ram ic memory cell count by using many ic?
For 16 by 32 bit word you would need 8 16x4 in parallel, with common address lines. However, whatever is driving the address lines needs to be capable of driving 8 inputs.

For 32x8 then you need to pair up two sets of 16x8 and decode a fifth address line to enable the required pair when appropriate. 

For 64x4 then you need to four 16x4s with common address and data lines and decode fifth and sixth address lines to enable the required device when appropriate. 

255x4 would mean 16 16x4s and you would need to decode 4 additional address lines. However, that is a lot of small memory chips. You would be better off finding and buying some bigger chips, even if it means not using all the address pins, and tying the remainder to a rail.