Virtual Computer

I have had the desire to build a computer from nothing for quite a while. When I say computer, it's not sticking a motherboard, memory and processor together that I want to do,.. I want to build one from the logic up. After studying the architecture of a pc at university I started to do some more reading on the history of computers and how they and the technology has developed over the years.

I've been trying to get a LEGO pc together for a while now. In theory it could perhaps be done, but it is highly impractical. The main problems I've found are friction and the marginal error that grows exponentially between logic gates. I've managed to create the And, Or, and Xor gates out of Lego. Each gate uses approximately 50 pieces of which 20 are cogs. The cogs are the problem. I've only got about 100...

So I've looked to TIM as well... The limitations here are space avaiable to design on is one screen; and the user cannot interact with the machine while in operation.

This has led me to the want to create a completely virtual machine in a program. My language of choice would most likely be java, but I also think Flash/Actionscript would be a good platform to try. The great thing about Flash is that it lends itself to being far more visual. My problem is that I am not very strong at all in Flash programming.

I think the best part about creating this TTL up computer virtually is that it doesn't pose any mechanical or resource limitations on the project.

Here's a link to an example..
http://goldfish.ikaruga.co.uk/logic.html