I feel uneasy answering you question. At one point, you were reluctant to go from a G30 to a G80 module because of cost, which is only about $4. Now you are looking at a GPIB to Ethernet solution, with a cost which has to far exceed $4. I have to wonder why you are using the Micro Framework. I have no idea what your product is, what is the development budget,
I can think of other platforms which might be a better fit, given the questions you have asked. But that would only be an uneducated guess.
So, only you can properly answer your question. Or, ask the person who is helping you with the parallel port to answer the question.