unsigned decimal to binary conversion in verilog

But what you describe sounds much like BCD coded input in my ears. You may want to clarify, what your "user friendly hardware input" looks like. If you possibly refer to the DE2 toggle switches, you should specify the intended switch coding.

Shifting by decimal places in a binary number system means multiplying or dividing numbers by a factor of 10. Early electronic pocket calculators have been somethings using decimal arithmetic (as mechanical calculators did before), but these days are long gone.