I tried to breastfeed our adopted dd. I took domperidone, I pumped before she was born, I used the Supplemental Nursing System (that thing is a royal PITA!). I had breastfed one child already, so it was supposed to be easier for me than for a woman who had never bf before, but I could never make more than about half an ounce a day. At first I felt like that tiny bit was better than nothing, but soon it became far too much work for far too little milk, so I stopped.
Why did I do it? Not because I'm "cracked"

, but because I had such a great experience bf dd#1 and I wanted the same experience with dd#2. The nutritional advantages of bm were even more important to me, specifically because I didn't carry her and didn't have first hand knowledge of her pre-natal care. Plus, if it goes well and you don't have to supplement, it's so much easier than bottle-feeding. I really dreaded having to worry about keeping formula cool on outings, and having to wash all those darn bottles, when I was so used to having an easy supply on-hand and at the right temperature at all times.
Anyway, I think formula is a perfectly acceptable substitute, too, so I had no qualms about quitting when it didn't work out, although I would have preferred to bf. Also, I don't believe in the bf=better bonding stuff. To me, it boils down to the interaction when feeding, and as long as a bottle-feeder cuddles and interacts with the baby, rather than propping the bottle, they will bond just as well.
There is an adoptive breastfeeding website that is wonderful if anyone is interested.
Adoptive Breastfeeding Resource Website