But as it is fucking hard! (besides vanitigen not working full-length address)
I have already seen another all upper case vanitygen address in a sig on this forum so I think this must not be correct (at least with the current version).
That's my address
1QBDLYTDFHHZAABYSKGKPWKLSXZWCCJQBXThe problem is not length, it's how specific of an address you are looking for. There are about 5833 possible address, so if you want to find a very specific one (such as 1BitcoinEaterAddressDontSend..), then you have a 1/5833 chance of finding it on each guess (infeasible*). However, my address was not a search for a single address, it was any address of all capital letters. There are about 2633 such addresses. So the chances of finding one such address on each guess is 2633/5833 = (26/58)33. That is actually in the realm of feasibility -- it is about 1/300billion
* 1/5833 = 1/15599970876632771988160814054146447252125923204784443097088