I've heard a lot of people talk about this, but never seen it done. Superjpr has a really good point about the vibes from an offset bolt. The hack and tap kits are really cheap for a tj, like under 100$ not including the driveshaft. As far as making your own using an xj slip yoke the straps are closed so you'd never have a way to get your driveshaft off and on. You'd need a strap type yoke that bolts. Most of the time people want to run some sort of a dual cardon setup off of the transfercase in which case I'm not sure how you could even find a slip yoke that would bolt in like the ones you see on the front driveshaft of an xj for example. The 231 output shaft is also pretty hard metal and I don't know how people tap metal that hard, it must be possible, but I wouldn't wanna do it. Plus when you push in the yoke all the way on a yj or most xj's it smashes the seal, so you'd have to find something to put inside the yoke, like one or many washers, to space it out far enough, which could cause another balance problem. On a tj which is what I think you have judging by your pic, you wouldn't run into that problem, just the strap problem. I've always wondered if you could call a driveshaft shop and have them build a slipyoke with the the straps or a flange and use that. For a tj they already sells something like that. Even if you could do that, and drill the hole straight, and tap it well, and find a way to space it far enough out (if by chance you do own a yj or xj), you'd end up making your driveshaft shorter. I usually drive xj's so that was never a concern of mine, but for a yj, tj, owner this could cause a problem. One time I ruined my rear driveshaft on my xj in moab and had to remove my slipyoke put a ziptie inside and tap it on so I wouldn't loose oil in my transfercase, then drive home to slc in front wheel drive. So I spent a lot of time contemplating a really cheep way to do a sye. I came to the concusion that it was more worth my time to just keep a spare driveshaft.