Here is the Excel one I've made. Perhaps you can use the calculations as a base. It is very primitive still, but makes for the most basic needs: i.e. technology % on the unit and its change into the designated Support/C-Bills, etc. By the way make the B column wider that C-Bills show correctly. :P
Thanks. I've got the math though. The trick is to be able to reverse the process because people buy things in support points and Cbills and then you need to work backwards. The trickier, erm, trick is to make it happen all in the same cells. I tried making a spreadsheet, but three-way dependency using VB scripting crashed Excel. I think now that I've used the right event handler in VB itself, I might be able to get rid of that button.
Here's what it looks like. You can enter in any one of the three currencies and out pops the other two. I *think* I know how to get rid of the button and have it calculate on the fly, but we'll see. Now someone just has to show me how to do HTML layout to look like this and I can work on the javascript.
*Also, I'm really unhappy with how packaging is done with VB. I assumed you could just get a portable exe to run (maybe with a popup complaining about wanting .NET runtime) but nooo. You actually have to "install" the silly thing like a full size program with libraries. If I want to make something reasonably portable it'll have to be Java or some-such thing.