There are many Nalegene bottles that are suitable and trustworthy (definately don't leak and can take a beating). My favorite was an 8 oz. low rectangular shape, with a wide (1"?) mouth. Nice and stable for drawing and dispensing with a syringe. But "suitable and trustworthy" are a drag on my DIY gene...
There are lots of bottles that can be reused as alcohol containers, but I shifted to the ones that actually came prepackaged with alcohol, like Purell and ~7 oz. plastic wine bottles. My paranoia is a cap designed for some other liquid could fail when alcohol starts to "eat away" at the seal, or worse, interact with the plastic itself. At least with these, there's comfort knowing that if it was going to fail, it would have failed already--at least chemically.
Purell comes in a variety of sizes, and most are in a slender rectangular shape. The wine bottles are round, and are OK for "body warming." They also have a nice metal cap that should last a long time. (I don't have enough "run time" with the wine bottles to be sure.)
As mentioned already, clear bottles are much nicer to work with, either by simply judging how much fuel is left, or with a little work, by drawing graduations on the side.
And I think the most important thought on using DIY alcohol fuel bottles is to bring a spare cap: I had a cap on 3 oz. mouthwash bottle crack while tightening it--fortunately, this was only used for body warming.