Whoa what are the chances?
My new boxed DC controllers arrived in the mail this morning and I have been trying to do exactly the same thing and having the same problems. I got as far as using x360ce to make them appear as xinput controllers, and everything would be fine except it registers the stick as moving left constantly even when there is no input. Same issue I guess. That was where I got pissed off and gave up just now. So I did a google search and found this thread, great I thought. Then I noticed that it was from today! What are the chances haha, I was trying to do it at the same time as you. So anyway I will try xpadder, The only thing I was worried about was if it will be be a problem that the stick is binary cause its mapped to keys instead of analog response? Is that likely to affect any games negatively?
I ordered rumble packs and VMUs for the controllers... I had dreams of using them all just like an original dreamcast with an emulator, but now with all the trouble I have had just trying to get a damn controller to work I assume there's no way to do that... Will the rumble packs work at least? The only VMU thing I see is for a g27 keyboard which I happen to have, except its on my desktop and the emulator is running on a living room box.