Hi gopalakrishnan narayanan (And I think we can all be grateful that I didn't have to try and pronounce that),

Go for it! Or, if you'll tolerate me stealing a marketing slogan, Just Do It! You are absolutely right. The benefit to be derived from building a universal programmer is not to have a universal programmer, but to understand one. The first time I hooked up a µ-controller with ISP I used Hyperterminal to download the program and watched everything on an oscilloscope. Obviously I didn't do this because it was the best approach, but it was the most informative. I even wrote the machine code (to turn a port into a ripple counter) and translated it into Intel Hex format myself.

And building the circuit board to make one work is yet another worthwhile challenge. There are a boatload of physics that can go unnoticed when trying to make digital circuits work.

A final thought about the impending extinction of universal programmers. Suppose you do build a project that has market? How many units can you program in eight hours by plugging them, one at a time, into a serial port?